If you move to install Steam on Zorin OS 16, you may find yourself falling into a dependency nightmare. You may see "Dependency problems. Steam requires.... But it is not going to be installed."
This is caused by the Focal Fossa Repos containing (an ever so slightly) higher version of some dependencies than the i386 counterparts required by Steam.
This necessitates downgrading the packages (by about .1 version...) in order to install Steam.
The easiest way I have found to resolve this is to use Aptitude.
sudo apt install aptitude
Then use Aptitude to install steam:
sudo aptitude install steam
Aptitude will ask if you want to leave packages unconfigured first. Answer
n to this. You should then be able to answer
y to all following questions to downgrade the necessary packages and install Steam.
Once done, please be sure to go to "Steam" on the Menubar of the opened Steam Window and select Settings. Move down to the "Steam Play" tab and check the "Enable Steam Play for all other titles" box to on- and "Run other titles with: Proton Experimental".