I’m pretty sure every compositor worth its salt (that is, kde or wlroots-based) reparents on fullscreen. KDE also does variable refresh rate and at that point I’m happy – I’m not playing competitive shooters any more and VRR is such an upgrade I’m not even noticing frame rates dropping. Back in the days not hitting 60 was terrible, sometimes I had to settle for 30 (though before LCDs you could do rates in between), now I can go “ah, around 40-50 but I like the bling let’s keep it at that”. Dropped frames are simply magnitudes worse than delayed frames.