...the GNOME/Apple hacky way, that is rendering at an integer multiple and then downscaling as needed. It works, but it's not optimal, and won't ever be as sharp as it could be.

The Gnome/Apple way is also apps can opt out when they do their own scaling, such as browsers, and can just stream the output directly at 1:1.

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".