I recently switched my Full HD monitor to Quad HD (native resolution 2560x1440) and encountered a problem with game's interface resolution. It appears blurry, looks visibly worse than it used to on Full HD and it applies to all interface elements: subtitles, icons, frames, maps and main menu loading backgrounds etc. Only hero portraits seem to be intact.
Switching to 2560x1440 also changed a thing in graphics options, as from now on, an option of 1080p or 4K HUD and HUD scale appeared, which was not present in 1920x1080. There appears to be no difference between 1080p and 4K HUD, it remained blurry in both, changing it's scale didn't make a difference either. I've also read, that the 4K HUD option didn't do anything even on 4K displays.
It's kind of weird to me, that game from 2017 didn't consider someone would play on a resolution higher than Full HD and didn't make the interface resolution scale.