Fractional scaling is a 99% solved problem at least on KDE, even with Wayland it seems to work fine for me. Just a few apps are blurry which I don't use.
The fix, unfortunately, is blame the hardware. Desktop monitors that don't approach standard DPIs shouldn't be still produced in the 2020s, 24" 1080p and 24" 4k are perfectly common and optimal for their intended uses.
And yes, I think 27" 1440p shouldn't exist... it isn't an integer multiple of 1080p (thus a poorly handled edge case of scaling rasterized media resources, ie, videos), but also, if you wish to maintain proper intended DPI scaling for ye average asset, 1440p needs to be 32".