Affinity could do what Adobe does, as well as others. They have to add their own UI Scale feature.
Running a 1440p monitor Windows properly suggests and selects NO system wide scaling. Which is a value of 100%. What Adobe does is add in their own UI scale code to let you use either the Windows scale or another value. On a 1440p 125% works nicely for Adobe. This scales not only the text, but also the tool icons and menus. YES, you can use the font size option in Adobe to change the scale of all UI fonts only, and that is another option.
I use this in other Adobe apps where I DON'T want the all of the interface scaled. (tool bars, buttons, etc) Point is, they give us options. Flexibility. It's just nice having PER APP control over this UI scale issue. Instead of having to force a UI scale across all of Windows.