SGTools: Solutions for "Not all wins are registered" after deleting game?

Only thing you can do is use Steam's automated support option to undelete the games and re-add them to your library.
Then remember to never delete any of your SG wins in the future 😒

I was wondering if it would be possible to have an account that legitametly actiavated all won games to be registered as such, even though some of the games have been removed out of the library.

Not unless the giveaway creator agrees to delete the giveaways entirely. I'd suggest un-deleting those games you've won and instead hiding the games in your library.

Why delete a game that someone gifted to you? Thats really offensive for the guy that created the giveway as propably he wanted people to try it and not delete it. If you arent interested in some games why join those giveways in the first place?
Just hide them in your library and dont join evey giveway that you can join.

the easiest would be that you could apply your OCD to sg instead, and keep your account with all your wins activated.

if not, you can ask giveaway creators you won from to delete those giveaways. it's not a nice thing to do and many will ignore or deny your request, but you could offer them something in return.
you could also take a suspension for those games and live with it, but you will be seen a a rule breaker.