Upgrading any modern iMac is a nightmare for anything other than RAM because you need to remove the very expensive screen. My 2020 iMac will never need any kind of upgrade other than RAM. The key is to buy one with a large SSD and powerful GPU.2020 iMac is nice machine, but do not buy it if you plan to do any kind of upgrade. For me the best choice is 2017, it has pretty much everything you need and can be found at acceptable price. M1X iMac will definitely be a noticeable upgrade but it is still not sure at what price.