You have my sympathy. I bought the Power Mac G4 Cube literally less than a month before it was dropped from the product line. I liked it, but what can you do? Be pissed, I suppose, and I was for a long time.
Before I upgraded the OS in my iMac to Catalina, every Steam game I had was giving a warning that it would no longer work under that OS. That prompted me to fix my daughter’s old Windows computer and that’s dedicated solely to gaming and I use my iMac for work, media server, and general goofery.
Has that changed? Is Steam releasing Catalina capable games now?