Borderlands 2 GOTY Russia

https://www.g2a.com/borderlands-2-goty-steam-cd-key-ru.html

It's a Steam gift copy.
Steam gives you warning about redeeming it/playing it with a proxy.
I intend to investigate this as Google has given me mixed answers.
As far as I know you won't get banned for having this in your inventory, they probably won't ban you for adding it to your library either assuming that warning message is just for show and it doesn't stop you even on a non-Russian IP.

One thing that can be tested and should be 100% safe to your main account is making a dummy account, activating and installing the game with a Russian IP and then activating Family Share then playing the game with your main account from your dummy accounts library. I read somewhere that worked for one person, no idea if it still does.

Replaying a fun game for easy achievements may just be a pipe dream in this case.

Family Sharing doesn't work for region restricted games really. You still have to be in the same region as the game to play it, even if it's family shared.