I would like to emphasize that it’s not only the speed of the local network connection. Also computing power of the router is important, as too much load will put a lot of strain in the CPU of the router.

Have you seen the PSA x265 4K Versions? I find them relatively good. But what is your opinion?

Just for your information, your router/network must be robust enough. I was using the router provided by my ISP and the devices streaming from my NAS were being dropped when streaming 4k (~15GBs), I struggled because I thought it was a problem from the devices but it was in fact the shitty router. Once I updated, I had no problems anymore.

Ahh the good ol’ times, I was once adventurous like you. That’s ok, my recommendation is to make a backup of everything important that you have, if you use banking in that computer just monitor your credit cards and accout. Also it is a good idea to use KeePass or Bitwarden to handle your logins. Once you have done all that just reinstall windows. Yes it is tedious but if you are sailing the seas you need to have a escape plan. Have your backup up to date, when I was younger I had an external drive that I would update before installing dangerous stuff… That after I learned the hard way.