i avoided electron based apps for this very reason – that x-platform capability means the app doesn’t look/work native on any OS
as for font sizes being a challenge due to the different screen sizes, that’s exactly why the option is needed and after quickly playing around with it, the problem seems to be as easy as manipulating the value for a single css selector in electron/chromium…
html { font-size: N%; }
this is easily set in dev tools and seems to work across the entire app so, offhand, i don’t see why it would difficult to implement