You can no longer install Windows 10 without online account. The best you can do is delete it after. You could use a disposable account, though. I don't see what's so horrible about that.
About MX Linux, like any Linux distribution, is compatibility. If you want to play games, use design software, etc., you won't find anything better than Windows.
If switching to Linux was that easy I would have done it ages ago, but it's not.
I guess you are looking for hardware recommendations.
What, specifically, will you be doing? If you want hardware recommendations you should provide a few basics:
- Software that you'll be using. (Will you be running many things simultaneously?)
- Screen resolution.
Those things should be more than enough for anyone here to give you good advice on what you should buy.
Advice: Don't buy a pre-built computer. Just buy the components and build it yourself (unless you want to buy used products, in which case buying components is a bad idea because there is no way of testing them).