I recently installed "dvdisaster" from Debian. The provided version has the GUI disabled, on the grounds that it's written in GTK2. It's just a single-line configuration change, so I recompiled with the GUI enabled.

It's been a long time since I last used GTK2. I was shocked at how much faster it feels than GTK3/GTK4 apps. Load time is almost instant on my old computer, and no perceptible latency anywhere. There's no arbitrary 60fps frame rate cap like with more recent GTK versions (while running on Xorg). There are no annoying animations. GTK2 was already perfect and everything since then has been a downgrade.