I do. I run Fluxbox on PostMarketOS. I use dino with jmp.chat for mms. I use emacs diary+git for calendar. I have some custom power management service I wrote shortly after getting the phone so it gets long battery life. My bank and brokerage both have decent web sites.

I'll never go back to a non-Linux phone, I'd rather not have a phone at all than tolerate the older mobile OSes.