As others have already (somewhat) alluded to; it’s best to buy a laptop from a company that offers devices on which Linux users are first-class citizens. Therefore, any device that specifically fits your needs (hardware-wise) from either NovaCustom, Star Labs, System76, Tuxedo etc should fit the bill. Furthermore, it’s worth noting that Nvidia GPUs have a known bad track record on Linux. The possibility exists that you won’t even notice it on any of the devices sold by any of the aforementioned vendors. However, I’d argue it’s still mindful to be cautious.
Should I better buy all of AMD (if yes, which CPI, GPU) or Intel/Nvidia? Or Intel CPU and AMD GPU? Which combination is the right one with best performance for a casual gamer? I prefer FPS games, if that’s important…
AMD has been doing very good for some time and the fact that the Steam Deck is powered by AMD is very telling of what the current status quo is. However, I don’t think it’s a hard requirement. Sure, going full-AMD has it’s merits, but you should be fine regardless.