The new post Jony Ive design and limitation to 24 inches make it undesirable. I know a lot of folks with older 2007 - 2019 iMacs but none of them who upgraded from those have the new 2020+ one.
I did have a 2010 Mac mini server, don't remember how it compared to the non-server one other than having dual HDDs instead of the DVD drive. I put them in RAID-1.