Thanks for the ideas, guys. To clarify, I am trying to access files in a Google Workspace business account. In that environment, you have 'Shared Drives' - essentially cloud drives set up at a company or team level. These are different to your 'My Drive' home directory (your personal storage space) and to folders other people share with you. To illustrate, here is what I see in Pop!OS:
If I click on the 'Shared Drives' folder, it reveals all of the company data shared across the team.
In Zorin Pro, I just see the contents of 'My Drive' - the 'Shared Drives' do not show up at all.
This post I found while researching which suggests that what I am looking for is a 21.04 Ubuntu (Gnome 3.36) feature:
We'll probably get this when Zorin moves forward to a 21.04 foundation.
If anyone does have any ideas in the meantime, though, I'd be grateful to hear them, as seamless access to Google Drive data via the native file explorer is pretty handy.