My advice would be to wait until the M1 Max version of the Mac mini comes out. At Production Expert, we have been running some tests on an M1 Max powered MacBook Pro with 64GB of unified memory and frankly, it is amazing.
In the
first tests, we compared it to a Mac mini 2018. We have since done further tests with the new HD Driver for HDX systems and also the new video engine and we will be publishing these very soon.