Look, if it's ok to say don't buy nvidia graphics cards and expect to use Wayland, why is it not ok to say don't buy mixed DPI and expect to use X11?
Mixed DPI is a giant PITA, and high DPI is also a PITA, so just buy regular DPI monitors that are about similar. :P
It’s still a hard sell when everything just works on Windows and macOS. It’s yet another reason why someone won’t pick up Linux when 90% of the features they want are present.
On windows I just plug my external monitor with regular DPI and it auto-recognize that this external monitor have regular DPI and size it acordingly while keeping the HIDPI of my laptop perfectly untouched and also auto recognized.
While on xorg, goodluck with that.
On Wayland it works, but require manual intervention of enabling fractional scaling and setting everything manually.