Cannot save or open documents (as box not popping up)

The computer is not responding when I click to open or save. It makes me think a box is popping up somewhere but out of view. I have now spent 2 days on a model that I do not know how to save. Please help! Thank you.

Do you have more than one display attached, and might the Finder-type window be appearing on a display that you are not expecting?

There is a reset button in [menu] SketchUp > Preferences > Workspace.
You could try that.
If you had another screen attached at some point, check the System Preferences of the OS (Apple logo top left) > Display to check, I noticed it sometimes doesn’t revert back and stays in dual monitor mode.

Hi, I haven’t used two displays on one model but I have a shared iCloud Drive that I access on 2 different laptops. I got my new laptop last week and accidentally uploaded the 2022 version, I have since downloaded 2021 (which I have a license for) and have been using that successfully. Do you think the problem could be to do with that?

I would not think that the use of aniCloud drive or similar fancy storage would cause Open and Save As dialog boxes to not appear on screen, no.

Does your Mac’s keyboard have a button to expose all windows? On my ancient keyboard it is the F3 key. Maybe try that after selecting Open or Save As, and see if there is a dialog box hiding under some other window?