stalked-for-the-last-18-months "I badly need GrapheneOS to literally save me!/iphones can't be hacked" an operating system cannot save you and this is a bad way of looking at security.
I agree with yodec. Install a live system like Tails until you figure out what's wrong.
We can't really help you without more info, but if you really want to 'power wash'/'wipe' everything that could be infected in an extreme way:
I would suggest backing up important documents (non-executables) onto a storage device. Reinstall your OS on your laptop (can make a bootable windows installer USB fairly easily.) If you really think there is a firmware based rootkit in your computer then I would buy a new laptop (rare for firmware based attacks but I guess they do happen in the wild its not impossible)
Note your important/infected online accounts, change their password and use a password manager. KeepassXC is a good one. If you use the same password for each account then thats how they probably got in to your bank/roku/etc.
Contact your bank if you haven't yet, tell them you were breached and need help. The money that's stolen is usually insured. (FDIC protects up to $250,000 so i'm pretty sure you can get that $50K back)
If you are really, REALLY, R E A L L Y sure they got into your router. Buy a new one, or contact your ISP if you have one of theirs and ask for a new one.
Security is not a case of things being 'unhackable' and that word is a misunderstanding of the concepts behind it. I would read up on common security practices for individuals. The best two I can give are:
Don't download (and execute) software you can't 100% trust. Assume the software could do anything to your computer and you are trusting the people who wrote it to not mess something up (intentionally or unintentionally)
Use different passwords/security identifiers for each account. Try to use 2FA/U2F/FIDO wherever you can.
Another thing, 'you include an ID when its installed", are you referring to the boot key ID? You don't have to give any 'ID' when installing GOS so im a bit confused.
Last thing I would say. There's some red flags in your post of strong paranoia. Constantly feeling watched, thinking people in your life (girlfriend, neighbors, etc.) are out to get you, etc. are sort of warning signs. Then again, I would tweak out a bit if I lost $50K TBF. I would just contact your bank and try to get FDIC insurance on that lost money.
But I would talk with a health care provider once you do, if for anything, because paranoia/fear is 100% a possible wedge in a social engineering situation. Think those calls you get from time to time that say 'Hello, we are [your power company] IF YOU DON'T PAY $1000 DOLLARS IN THE NEXT HOUR WE WILL CUT OFF ALL ELECTRICITY FOREVER', fear is very exploitable.