Yeah, fractional scaling is absolutely the one thing that I miss on Linux. On X11 it's too slow and laggy. On Wayland I have... Wayland issues.

I don't entirely love MacOS (mostly because I can't run it on my desktop, lol). But it does fractional scaling so well, I always choose the "looks like 1440p" scaling on 4K resolution, and literally every app looks perfect and consistent and I don't notice any performance impact.

On windows the same thing, except some things are blurry.

On Linux yeah I just have to bear huge UI (x2 scaling) or tiny UI (X1) or live with a noticeable performance delay that's just too painful to work with.

It seems wayland has fractional scaling, but it is recent, but the bottom of this is high DPI handling should be handled at the GUI toolkit level. Compositor scaling is just a dirty fix for legacy GUI apps.

Try just setting the correct dpi for your monitor and use a hi-dpi theme. No scaling required. Pixel perfect graphics.