My iMac Pro T2 chip is able to load Sonoma. President our local group has a 27inch iMac - it can’t. He was a bit cross about that. At the time we had a lively debate about the 27inch models and I said I was hoping a bit of future proofing.
Initially had some problems because of the T2 chip constant crashing but put it into my favourite Apple qualified tech who wiped the drive and set it all up again for me under warranty and had no more problems.
But I haven’t gone forward as yet with Sonoma - I’m told it’s heading more to iPad like and I wouldn't be impressed with that.
:-)
Jude