As someone who just uses Linux but doesn't write compositor code or really know how they work: Wayland supports fractional scaling way better than X11. At least I was unable to get X11 to do 1.5x scale at all. The advice was always "just increase font size in every app you use".
Then when you're on Wayland using fractional scaling, XWayland apps look very blurry all the time while Wayland-native apps look great.
xrandr --output HDMI1 --scale 1.5x1.5
As a similar kind of user, I set Xft.dpi: 130 in .Xresources.
If I want to use multiple monitors with different dpis, then I update it on every switch via echoing the above to `xrdb -merge -`, so newly launched apps inherit the dpi of the monitor they were started on.
Dirty solution, but results are pretty nice and without any blurriness.