My opinion about how you get this is I think you may have downloaded a software that isn't downloaded from the original website and may be infected with that malware.
That could be the answer since, I recently got this device. So a lot of software had to be reinstalled.
Reinstallation of software shouldn't bother you more than your safety and the first mistake you made is not formatting the entire hard drive since the OS was bought from someone. In the crypto space, the only person you can trust is yourself.
But that's not what I'm worrying about. I worry about windows defender not detecting it.
Most detect viruses but do not always detect Clipboard malware. After having anti-virus and anti-malware on your computer you shouldn't rely on them to detect every attack because they only work the way they are programmed.