Clearing up memory on my office mac pro seems impossible

Optimize storage space on your Mac - Apple Support and Free up storage space - Apple Support describe how to increase available storage.

If you already followed those suggestions and nothing appears to have changed, allow a day or so for the available storage to become evident. That amount of time is neither published nor can it be reliably predicted, but a day or so ought to be sufficient.

Memory is what is provided by the Mac's installed RAM. You are talking about storage, not memory. Your solution is to install an external drive, copy files onto it and then delete them from your HD. (Be sure to also empty the Trash or the space is not reclaimed.) Then you will reclaim the needed storage.