I disagree with your take on the framework. The inferior build quality alone is not a good enough reason to say they aren't worth it over an X1 Carbon or XPS. Neither of those offer easy repairability and the XPS has atroucious IO.
I use a Framework and have run it primarily using Plasma Wayland and Hyprland. Both of these have had fantastic HiDPI support. Both can scale Wayland and Xwayland apps seperately so that you do not have any fuzziness and both support Wayland's newest fractional scaling protocol.
If you're running a modern distro (one with good wayland support), you should have no problem with hidpi. The more recent comments in the thread you linked support this.