Ubuntu 20.04 just arrived with fractional scaling of the desktop available from the settings. Yes, you have to turn it on first to be able to choose fractional scaling of 125% or 150%, but finally you don't have to edit gnome settings to do this. Also, this time it might work as intended too...
Fix AMDGPU driver problems for your AMD video card in Ubuntu 18.04 after upgrading to a new kernel
Your AMD video card will probably work flawlessly out of the box without installing any additional drivers in Ubuntu. However if you are unlucky like me and experience random crashes, you might want to give the official drivers a try.