Windows Upgrade Help and more

You could also try disabling fast startup in Windows power options, as that sometimes conflicts with portable drives. Let me know if that works.

Yeah, that processor is just one generation too old for Microsoft's official list. You could look into the registry bypass, but it's a bit of a hassle. Hope that helps.

This. You could also look into a clean install using an ISO, which sometimes bypasses the checker, but it's not officially supported.