I always add these GNOME extensions to fix a few annoying quirks in Ubuntu Gnome (20.04), they should be included by default in Ubuntu, in my opinion. Arc Menu requires gnome-tweaks:
gnome-tweaks
From your terminal, run this command:
sudo apt-get install gnome-shell
Reboot your computer, click on the little Ubuntu icon next to your login name and select select 'Gnome Classic (No effects)'.