Can I use an SSD drive with Monterey as my main drive for an older (2013) iMac?

My office computer is recent enough to run Monterey, but my home computer (on which I do much work) is a 2013 iMac that is limited to Catalina. I keep my 100K+ photos in Photos on a portable drive, and I need to be able to access them from both places, but the version compatible with Catalina does not work with Monterey. Can I run my older Mac off of an external SSD drive that is configured as a Monterey main drive? I've seen conflicting statements about this. I know the 2013 iMac is a dinosaur, but it's otherwise running fine for me. It's kind of mission critical that I be able to access my photos from both computers, though.