New Server

A basic Linux/Windows VM or Mac Mini would be more than enough for your environment.

Or if you have the internet bandwidth consider using one of the cloud DP options.

a Mac mini would do fine for your environment. The good news is that you don't actually need the former macOS Server product to do it with now as ALL file sharing capabilities are now built into the System Preferences under Sharing. There used to be limitations to concurrent connections, but according to my Apple rep, they removed that restriction.

Now, I'm going to be the guy that tells you...don't install this service on a Mac UNLESS YOU HAVE NO OTHER WAY TO DO IT! I say this as a Mac nut who hopes to always be a Mac nut.

It's honestly a waste of a perfectly good Mac that you could put in the hands of your end-users. Apple now uses SMB by default and we've been using our DP over SMB for almost a year now. If all this server will be doing is hosting files for your DP, run it on a Windows VM or Linux VM. If you don't have ANYTHING but a Mac, then go with the Mac mini and try to get one with an SSD for speed. As for RAM, keep in mind that Mac minis are not upgradeable so consider how much RAM/storage you are going to want in say 3-4 years (or whatever one lifecycle is for you folks). Add that amount of RAM when you buy the Mac mini, not necessarily what's cheap right now. This is another benefit of a VM or a non-Mac host....you can put in only what you need now and upgrade it later to what you need later.

Cloud DPs are very useful, but know your pricing with Amazon upfront. I hope to one day see Azure as a supported Cloud DP given that we get access to Azure Servers at a ridiculously cheap rate as a school district.

Hope this helps.

We have about 2,000 active Computers/Devices.

Being an all Mac Shop we also had to make the same decision. We decided to move away from MacOS hosting our MySQL Server and decided to go RHEL due to a lot of problems with MySQL on the Mac Mini Server, you may not have this problem, but if you plan to grow, consider moving to a Linux Box. I've been advised that it would be beneficial to move Apache Tomcat over to the Linux box as well.

We went Linux because the CLI is Unix & for the same price as a mac mini, we got a beefy RHEL Server. 110% happy with our decision and saw increases in speed immediately. No problems since. Before, on the Mac Mini, every 2 weeks we had issues. We had to keep minimum log size, yatta yatta, etc... Highly recommend going Linux for hosting your JSS.

If you have a substantial number of iPads as well, or a lot of Mac App Store software that doesn't come from your policies, then you might also wish to consider running the Caching service on a Mac Mini.