Menu bar and toolbar of few applications are very tiny in ubuntu 20.04

The problem is with high def displays. So, what I simply did was to decrease the resolution from 1920X1080 to 1600X900 now the font is fine with all apps.

I had the same issue recently on my main rig. Couldn't find any answers anywhere so I resorted to a fresh install (had originally been a 19.04 install, upgraded later to 19.10, then eventually to 20.04).

The issue hasn't resurfaced on this machine since, but this morning I rebooted the media centre to find the same problem... so I've been back to searching for solutions (incidentially, it was also originally a 19.04 install, so my initial thoughts were that something had gone awry through the upgrades).

As it turns out, it's a bug affecting Nvidia users, so most likely is what's affecting your laptop (nice unit btw).

I found my answer here: Ubuntu 20.04 interface font too small after restart, even with high scaling factor

Bug report here: Shell text is too small in mutter 3.36.4-0ubuntu0.20.04.2

I hope this helps.