Bionic Commando: Rearmed.... low violence

If you win a key on sg, it should technically work fine, because the giveaway creator can restrict the regions the key doesn't work in, so you shouldn't run into keys that aren't for your region. So assuming you can see the game in the steam store from your country, it should be available for purchase, and so, if you win a key that's redeemable in Germany, it should work fine.

You are probably limited to the German release
https://censorship.fandom.com/wiki/Bionic_Commando:_Rearmed

My version from one of the last HB(?) bundle is, in germany, the full version. Nothing about low violence in the licence activation page.

I assume, because of this, that nearly all from the won keys on sg, now and in the near future, will be totally fine for you.

According to this comment in the bundle thread, German customers receive, and can activate, the same ROW package as almost everybody else.
In fact, the German version is just a sub containing the exact same underlying appID and content as the global release, but with an extra low violence depot.
You likely got given an actual region locked key, i.e. RU/CIS (activation lock) or LATAM (activation AND run lock).