I apologize if this is already answered somewhere but I'm curious what exactly a fitgirl repack is? I know it's a pirated version of a game but like is it just an installer or something? And if you imported the game into steam for example can you be "banned" or VAT (idr the term)
Any sort of malicious activity that's not bitcoin mining can be disguised easily within the background noise of normal CPU usage. If you're getting pwned, assume you're getting pwned for longer than the duration of the install program - any strenuous pwning could be spread out across hours or days if they really wanted. If you're ultra-worried about whether repackers are trustworthy, you can always source clean game files and crack the game yourself.