Legacy apps have problems in windows also, I guess in MacOS now basically you are not able to run them, but 3 years ago I remember same issues with old apps, blurry or pixelated…
The main issue is gnome not letting apps to scale themselves, whereas kde has just a toggle for that. So in gnome you have consistent size across monitors (cool) but blurry apps when running in xwayland (horrible)
Do you have a link providing clear info on that? Because I have seen only comments, no serious analysis on security whatsoever…