Same. I was ready to pull the trigger but decided to check on OS compatibility. Glad I did. I typically upgrade OS each year when macOS x.1 comes out in mid to late autumn. Now I'm just avoiding it as long as I possibly can. Hoping the rumors about a Snow Leopard style update coming next year are true. I think most of those rumors have been for iOS/iPadOS, but macOS really needs it as well. And I'm tired of Liquid Ass!
Looking at 5K/6K options from ASUS, BenQ, ViewSonic, and LG now. Some of the reviews on Amazon right now seem a little sus for some of them, and some of them the price is high enough that I question if it's worth it for something that isn't Apple. Might also look into deals on the old 5K Studio Display. Or maybe even the XDR would come down in price. What I really wanted was just a 6K Studio Display. Doesn't even need 120Hz. 60Hz or 90Hz would've been fine! My studio is a light controlled environment, so I don't need something super bright, although better contrast would be nice at times.
I kinda wonder if they'll bring out a 6K XDR again next year. Perhaps they needed newer, faster Macs to power it at 120Hz?