Thanks for the tips folks! I'll consider this my problem and not the Mac's. This is my "work" computer and they only give us Macs with 256GB. (My 2TB Air at home doesn't have this problem, of course.)
I don't see any Recommendations at the bottom of Settings/General/Storage, so I'm guessing that I either already turned all of these on, which is a possibility, or our Admin disabled these, somehow. (All my files are in iCloud for sure.)
I'm due for a new machine in January, but realize I may have to clear space and for forget syncing Photos to this one... and probably stop syncing Messages as well, since that is taking up a ton of space. Thanks for letting me know what is "normal" here!