I'm curious. I know the 2017 iMacs don't compare in terms of speed to the Apple Silicon machines, but what aspect affects you the most, and what are the specs of your iMac?That will be fantastic. I am holding out for a M2-based Mac mini to replace my aging 2017 iMac.
My 2017 27" iMac Core i5-7600 won't get replaced anytime soon, as it has SSD and 24 GB RAM, and I mostly just use business applications (albeit sometimes with pretty heavy multitasking) with a bit of light photo editing thrown in. It still feels quite responsive. It gets Ventura, and will likely get two more years of security updates after that. Furthermore, there is no direct replacement for it, so I'm inclined to keep it a long while.
OTOH, I will replace my 2014 Mac mini Core i5 with 8 GB RAM with an M2 or M2 Pro Mac mini. I suspect though they may never release that M2 Pro Mac mini, and by the sounds of it, the M2 Mac mini may not come until 2023.