I'm using linux mint with fractional scaling on just one of my displays. (The other display is just 1:1). Everything seems to just work fine.
Well, except for an outstanding bug where after I log in, I get a duplicate, stationary mouse cursor appearing somewhere on the screen that just hovers over any open windows. Its annoying and weird.
But I find 1x scaling to be too small to enjoy on the QHD screen. Multiple integer scale factors are possible but it is a bit complex and when I did it machine was prone to crash...
That said I still love it.