Apple hardware tends to stay viable for a while, but they're finally old enough that the latest versions of Photoshop won't work on them 100%. Some features need a newer OS and Apple silicon for full functionality.
It'll be a while before I can afford to upgrade both, but a refurb MacBook Air with the M1 CPU should be doable between now and Christmas, and then maybe in January I can swing an M1 mini for the desktop.