I prefer the toolbar size in musescore 2 and there doesn't seem to be a way to revert to that.
Reported version
3.2
Type
Graphical (UI)
Frequency
Many
Severity
S5 - Suggestion
Reproducibility
Always
Status
by design
Regression
No
Workaround
No
Project
I actually work on quite a small screen, so the toolbars take up a large chunk of the score as they are currently.
I figured this was what the Icon size and Font Preferences were for, but adjusting them produces no immediate result and, upon reopening the menu, the numbers seem to revert themselves.