What 'pro server' software are you using?
If Apple's previous Server.app then you would not be able to run this on a brand new Mac apart from the current Mac Pro which is still the round-black 2013 model.
When the new Mac Pro is eventually released later this year according to Apple it will only run the very latest Apple Server.app which is now missing a lot of the previous functions. See - https://support.apple.com/en-gb/HT208312
An option is to look for a secondhand Mac Pro e.g. on eBay.
Note: A Mac Pro 2010 is effectively identical to a Mac Pro 2012. The only real difference is the speed of the CPU chip(s). It is possible to upgrade the CPU chips in a 2010 model so it then literally is identical to a 2012 specification one. I did this with mine.
Note: The Mac Pro 2010 and 2012 will run the very latest macOS and Server.app i.e. Mojave and Server.app 5.7.1.