I've used fit girl for a few repacks, including doom. I normally use a private tracker because I don't have bandwidth restrictions or slow speeds The doom one was downloaded a while back from fit girl so it is possible it has changed. However, I just installed a fresh copy of Windows 10 on a test hard drive, installed utorrent 2.3.5 (a private tracker I use requires it), and used the magnet link and downloaded and install. I don't see any suspicious behavior, pop-ups,
Although you have been torrenting for so long, it doesn't mean you didn't make a mistake, or got a virus/spyware/malware elsewhere. It could be some random dumb thing you have no recollection off.
I have no reason to defend these repacks, if ya don't like them don't use them. I think we would hear a lot more users with issues if there was some kind of infection in the repack. If I were you I would run a quick expirement. Perform a fresh install of Windows or use a virtual machine, download just a clean Torrent client, than this Doom repack from fit girl magnet link. If you don't see this same odd behavior, you'll know something else was a problem and you can track back and see if you can find what exactly caused your issue.
If you so this expirement and you can repeat the problems you had before on a clean install, than post further information and proof.
Or, you can just stop using the repacks. The only downside to this is if you legitimately got this malware from another source, you won't have traced and figured out the problem. Just because you have torrenting for a long time, doesn't mean you couldn't have made a mistake elsewhere. I've been an IT consultant for 19 years, and I still make embarrassing mistakes at time. It is dangerous to assume you will never make a mistake or miss something.
I hope you can solve the issue. I'm sure the forum here will be looking forward to what you find. Even if the problems your getting is from another source, it still is helpful information to post to ensure another member doesn't do the same thing. Good luck!