In 2021, unless you need touchscreen capability or play graphically intensive games, then your overall best bang for the buck is probably buying a Macbook Air, which will run PC software with Parallels Desktop or Boot Camp. I'm not a mac user so I can't tell you how easy it is to transfer over the settings but it looks simple enough on the Parallels
website. It basically runs most Windows software (excepting accelerated graphics games) faster than an actual Windows machine, and the battery life is incredible. If a real Windows machine is your preference then the HP Spectre x360 is highly rated.
Lisa likes it, anyway. With a Windows machine, the answer to your backup question is definitely yes. However, if you're looking for a 100% smooth, completely worry-free migration, my limited experience is, don't count on it, regardless of which machine you buy.
If you do get a Windows laptop, I'd suggest that 8 GB as an absolute minimum and more if the price differential is reasonable.
And I wouldn't worry too much about processing power. Even a halfway decent phone will easily trounce any human player with Stockfish/Droidfish.