I used a dumbphone for quite a while last year and honestly loved it. I have a small collection of them at this point since they are relatively inexpensive.
Today I use a Unihertz Titan Pocket which is technically an android, but looks like a Blackberry. I've gotten a bunch of comments on it. It will certainly do more than I need, but I've disabled the play store and use it mostly like a dumb phone, with the exception of streaming music, which the dumbphones obviously wouldn't do. I bought a dedicated mp3 player for that purpose, so that's not the feature that brought me back.
I switched because while I could absolutely use the dumbphone to do everything I needed to do, group texts were ultimately the thing that brought me back to an android. Though it's been a known issue for many years, group texting on Nokia's feature phones is just bad... when it works at all. I still keep an eye on the dumbphone market and will absolutely switch back when group text messages are sorted out.
I have some stuff at work that requires 2fa too. I have an old iphone with no SIM in it in my office, I use it for authentication and that's it :)