How to remove gnome settings from ubuntu 20.04 with unity desktop?

After you've install Unity Desktop and, logged into it, use:

sudo apt remove ubuntu-gnome-desktop
sudo apt remove gnome-shell

This works for for Ubuntu 16.04 to 20.04 and even 20.10 (Groovy). Source:

• Ubuntu – How to remove Gnome Desktop Environment without messing Unity DE? (Ubuntu 16.04)

Although article is written for Ubuntu 16.04, you can verify the package is still around for 20.04 (called Focal) by visiting Package: ubuntu-gnome-desktop:

Personally I use Unity all the time but like to keep both desktops installed. Occasionally I need to answer other users' questions about Gnome Desktop.

Note: ubuntu-gnome-desktop might not be installed

Because it is a transitional package since 18.04 these instructions from:

• Why and How to Install Unity 7 Desktop on Ubuntu 18.04 LTS

Tell you to simply use:

sudo apt remove gnome-shell

The article doesn't mention ubuntu-gnome-desktop needing to be removed. This article includes additional tips on setting up Unity Desktop.