The SS are not really represented in the game anyway, and so not the 'European' SS either.
I would plead though to give a few garrisons as osttruppen. They were reeaaally numerous, according to this video, which is citing a famous book author, between 1 M and 1.5 M Russians and slavic men served as auxiliaries. They were not all armed, by far, but surely it is worth 2 or more garrisons?
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