Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
We have some air-gapped computers that run test equipment at work that I have upgrading over time. Surprisingly even though the Windows XP era "legacy software" doesn't officially support Windows 11, I have had no difficulty installing and running it.
Likely, the reason this likely works is that...
If you blocked the ports on the network side and whitelisted access rules on the ftp server I don't see any harm in setting it up that way.
It still seems crazy that Windows doesn't have native sftp functionality built into their file explorer.
I have mine in bridge mode currently. As far as I am aware you have to connect with an Ethernet cable directly to it to log into the admin page.
https://www.xfinity.com/support/articles/wireless-gateway-enable-disable-bridge-mode
You can save your keybindings out of your "LIVE\user\client\0\Profiles" folder so you only have to rebind the updated controls. You can also save your custom characters from "LIVE\user\client\0\CustomCharacters" as well.
I use Keepass on my PC with my password file stored on my Google Drive. And then I use KeePass 2 Android on my phone that also syncs to Google Drive.
It also includes a password generator for when you create new accounts.
This is just an anecdote, but I had something very similar with one of my PCs a few years ago. I tried many different things trying to resolve it and discovered the issue went away when I replaced the power supply. Do you have a spare power supply you could try swapping in?
I use a foam display board (think school science fair displays). It keeps the PC from sinking into the carpet so the power supply intake isn't obstructed and it slides easily across the floor too.