"3.3 Your GOG account and GOG content are personal to you and cannot be shared with, sold, gifted or transferred to anyone else. Your access to and use of them is subject to GOG’s rules which are set out here, as updated or amended when necessary."
https://www.gog.com/support/policies/gog_user_agreement Even if it was allowed to sell your account, which it isn't, it seems like you are throwing away the baby with the bathwater. It is not doing you any harm to keep your account, plus you may want to replay those games someday or come back to download an update made to those games.
If you really want to sell your account, you are better off doing so on another site. This thread is likely going to be nuked once the mods see it.
It is unfortunate that gog made changes that obligated them to have to censor the store in Germany, but since they did they need to follow the law, as unfortunate as the law may be. I think you can still get around it using a vpn or trading with someone else.