It would be really interesting if the world of Superman: Red Son made contact with Earth 10. We would have a war between a Nazi-dominated DC Universe, and a Soviet-dominated DC Universe. It would be the ultimate interdimensional Russian front.
The New Reichsmen would battle against the Heroes of the Soviet Union. I had the idea to create an amalgamated version of Earth-10, by combining all the different versions of the DCU where the Nazis won WW2. With that in mind, the membership of the New Reichsmen would be. . .
Brunhilde (a valkrie from Valhalla, sent by Odin to support the Nazis. Powers identical to Wonder Woman)
Dark Arrow (nazi Green Arrow, team leader, and Fuhrer in his secret identity)
Hawkman and Hawkgirl (apparently have actual wings)
Leatherwing (nazi Batman, from the von Hammer family)
Lightning (nazi Flash)
Martian (Nazi Martian Manhunter)
Overman (Kal-L, whose rocked landed in the Sudetenland and grew up a Nazi)
Overgirl (female clone of Overman)
Ray (nazi version of Ray Terril)
Ringbearer (Colonel Hal Jordan, give a magic ring created by Himmler by the dying Reichsfuhrer, and charged to defend the Reich.Ring is yellow, and has the same powers as Green Lantern, but not the color or time limit weaknesses)
Underwaterman (heavily armored Aquaman with a crew cut, whose people were declared true aryans and invited into the Reich)
I wonder which team would be victorious? In numbers and strength, they seem very evenly matched)
I don't think it would be a good idea to try to merge Earth-X with Earth-30 with the Nazis who were part of the National Socialist Party of German Workers. Nationalsozialistische Deutsche Arbeiterpartei considered themselves to be the only true followers of Vladimir Lenin's doctrine, "Nazis" is the name that the Germans gave to the Socialists if they happened to confront the Arian Superman and the New Reichmen would probably consider Earth-30 as a "pathetic and inefficient caricature" when compared to "Nazi glory" and in turn the Superman Premier Russian of Superman Red Son would simply be outraged by the dystopic world of Earth-X and would simply refuse to admit that "that" is similar to the world he created. Who would win a clash probably would be nobody because both Earths are absolutely matched in terms of power and metahumans. The fact that the New Reichmen would probably use lethal power does not mean anything because Russian metahumans under the command of the Superman Premier Russian would probably also strike back using lethal power against Nazi metahumans and the Earth-X Nazi war machine is absolutely equivalent to the Russian war machine of Earth-30 where Russian technology is unparalleled thanks to the addition of Kryptonian technology thanks to Brainiac, which is the master computer and "brain" of all armaments and aspects of technology that Russians of Earth-30 received from Krypton and remembers, much more the computer, "Virgo" from "Ronin" by Frank Miller being practically a "Cyber God" and the Kryptonian super intellect of the Superman Premier Russian about metahumans Earth-30 also has its own version of the Justice League which is the Justice People's Heroes group formed by communist counterparts of the members of the Justice League which are:
Batman is a sought-after outlaw who fights for freedom who only occasionally watches and assists members of the super team Justice People's Heroes on certain occasions in exactly the same way as Batman from Justice League Unlimited Universe. He is the only one who is not fear the Superman Premier Russian besides President Lex Luthor.
Red Lantern a Russian counterpart of Alan Scott that uses one Red Power Ring of Rage made of a fragment of the "Red Starheart of Fury" created when the aliens Oans eradicated all the furious mystical energy of the Power Battery Central of Oa resulting in a Rage Scarlet Orb of Magic that fall on Earth in Russia that took the form of a Lantern being taken by this man and saved he from death in a railway disaster on russia's railways and that works energized by his feeling of rage and for his aggressive emotions but like the rage and the aggressiveness is a feeling that all of us already have experienced to a greater or lesser degree throughout the life and "Feel rage" by someone or something is a normal act of the human being he is not seen either as a "villain "nor as a threat" being a powerful and unpredictable ally of Superman Premier Russian integrating with him the super team Justice People's Heroes your Red Power Ring has the exact same powers as one of the Red Power Rings of Rage of Red Lantern Corps but none of its weaknesses being a Ring of magical power that is not as vulnerable to wood as the Power Ring of Sentinel / Alan Scott.
Aquaman on Earth-30 Atlantis adopted the modes of communism as a system of government more efficient than the imperialist monarchy and which is governed by Aquaman the Premier Atlantean ally of the Russian Superman and integrates with him the super team Justice People's Heroes
Wonder Woman Queen Diana of Themyscira in this Earth also adopted the ways of communism considering them as much closer to a true government of the people equal to the Greek ideal than the decadent capitalism of the USA and is also an ally of the Russian Superman and integrates with him the Justice People's Heroes group.
Shazam / Billy Batson here was born a boy from Slovakia and received the powers of Shazam and being divinely empowered by the Gods of the Slavic Pantheon growing up on the protection and guidance of Russian Superman his greatest idol, example and father figure and integrates with him the Justice People's Heroes group.
Captain Atom here is an officer of the Russian army who volunteered for an experiment with atomic energy that gave him fantastic quantum powers being placed by the Superman Russian in charge of command of the army of the Union of Soviet Socialist Republics being one of his best friends and totally loyal to him and integrates with him the group Justice People's Heroes.
Red Star, who at Earth-30 has always been a hero totally loyal to the ideals of communism, also part of the Justice People's Heroes group.
Cyborg (white Caucasian russian version of Victor Stone) is a technological Russian superhero who is a member of the Justice People's Heroes super team.
The Thanagarians Katar and Shayera Hol landed on planet Earth in Russia adopting the modes of communism as their due to its similarity with the Thanagarian government system and became two Russian heroes communist versions of Hawkman and Hawkwoman are also loyal members of the Justice People's Heroes super team.
The Atom is a Russian Soviet counterpart to Ray Palmer who controls a Bottled City Russian of Research Scientists in the Microverse who devotes his scientific knowledge and his intellect to assist the super team Justice People's Heroes.
Zatanna Zatara Zatharov a Russian counterpart to Earth-1 sorceress Zatanna Zatara who has the power to access and use the powerful powers of magic of the 5th Dimension and be able to perform prodigies comparable to those of the 5th dimensional Imp Mister Mxyzptlk, with the only limitation that the magic she channels from the 5th Dimension operates according to the laws of magic of the 3rd Dimension, but that is true, her powers were above that of her Earth-1 counterpart Zatanna Zatara in scope and effect, and thus far closer to Shazam or the Spectre. She is the official mystic of Justice People's Heroes.
Lady Flash / Ivana Christina Borodin Molotova is the fastest living super-speedster on Earth-30 being even faster than the Flash / Barry Allen of the USA and a member of the Justice People's Heroes super team.
On the USA side there are a few numbered metahumans who serve as soldiers of President Lex Luthor: The Green Lantern Major of the American Air Force Hal Jordan is a decadent and questionable morality version of Earth-1 Hal Jordan, Firestorm / Ronnie Hammond, Flash / Barry Allen and Commander Steel / John Henry Irons (black african american with the exact same powers of Citizen Steel / Henry Heywood III) are military operative under the service of the USA government as well as Doctor Fate that he uses as a mortal host against his will, the warlock John Constantine, Green Arrow and Black Canary two merciless uniformed vigilantes who don't care about using lethal methods against criminals, Vibe, Gypsy, Vixen a version much less secure of yourself and the morality of the acts he practices in "the name of Justice" of Martian Manhunter , The Elongated Man , Metamorpho and Black Lightning.
An eventual alliance between the USA and Earth-X is out of the question because President Lex Luthor would immediately hate the "Aryan Superman" even more than he hates the "Communist Superman" and would consider both as examples of "beings that minimize the human realization". Anyway, I don't think anything like that would work.