If you wait 3-5 years into ARM... they might bring bootcamp back because windows advances, all the stuff will be ported and running smoothly. Let the early adaptors pay for the evolution (and the headaches) and than smoothly transition to a well oiled system that has been running a few years. Not an idea that feels to terrible.
I will probably switch on MacBook first since my MacBook is 2015 (and honestly due to retina some stuff runs horrible, my 2012 iMac handles Lightroom classic so much better with the same RAW files it is totally crazy)... so if apple brings back ports OR the tech world manages to transition to a level were you don't need to cary around dongles to make your mobile computer work with friends, family and work associates that might be a legit option.
I am not even saying having one or two of these new ports is bad, i hear great things about external SSDs like Samsung's T5/T7... but, like, it's... been... almost four years they forced these ports on their customers and they are largely not used by the average consumer... there is being ahead of your time and there is just being silly and stubborn (butterfly keyboard anyone?). And than think of something as horrendous as the 12 inch MacBook on top of all of that. The MacBook line is due for some real hard work before i buy a new one. But as for my personal switch to ARM it WOULD BE the first in line way before iMac.
Heres a Tip to keep your current gen iMac a bit cooler.