Sure, I get it. No problem. I was mainly objecting to the “will not work” comment. They’re not requirements, they’re merely recommendations. If you don’t follow them, you’re not breaking the rules, you’re taking a chance.
I do have a lot of endpoints, but I rarely use many of them simultaneously.
Multiple endpoints and DSP work totally fine on my 2009 Mac Mini running Yosemite.
FWIW, I suspect this is one of the more authoritative posts on the subject:
That’s what I did,picked up a Dell mini pc with 6 core i5 9500 8gb ram 256nve for £180
I use Roon in two countries. I picked up an inexpensive reconditioned notebook with a small SSD for dedicated use as a Roon core in one location. This proved to be an inexpensive route for me. As long as it meets the Roon specs this might work for you.
I’m going to re-purpose my Lenovo 910 laptop for the always on, Roon server. I was looking at a new machine for business/everyday use; just moving the purchase up a bit.
As this laptop is currently my Roon server/core (not sure what the diff. is between “server” and “core”, if any?) and has not presented any Roon issues while using it for my everyday needs, I’m going to keep all my other stuff installed on it and not wipe it, so it only has Roon on it as was suggested earlier in this thread. We’ll see how that works.
I noticed my main Lenovo PC really struggling with my Roon library (126,000 tracks, integrated with Tidal and Qobuz) so I transferred the Core to a renewed Lenovo T410 laptop. Took a few hours, but not a hiccup since the change (two days ago). $135. I also used a renewed T420 to connect Roon via Wifi to my Schiit Bifrost via USB.
I have 1,400 tracks 
Wow, installed Roon Remote on this new Mac; logged in; connected to the Windows core device mentioned above; BOOM!
All my stuff is here in the Mac Desktop Remote App- network devices from the core app., playlists, settings, my whole KitAndKaboodle - playing from Mac Desktop Remot; super simple!
You could easily swap that 1tb hdd with a ssd in a 2014 Mac mini (7,1). Well, maybe not easily, but it’s doable.
https://www.ifixit.com/Guide/Mac+mini+Late+2014+Hard+Drive+Replacement/32815
A little bit of time and an additional $50-100 bucks for an ssd and you’re golden. You could then repurpose the 1tb drive as external storage.
2014 macs can have both a proprietary M2 SSD drive and a 2.5 in SATA drive in the case (a regular M2 won’t work)
OWC do the proprietary M2 SSD drives and a kit with the tools and cables you need.
So you could add a small OWC Aura SSD for the OS / roon DB and keep the 1TB drive for media.
As @ffk says it’s a proper job to get inside the Mac mini to do this.I’ve done a couple - and found it fine as long as you have the tools (many kits include them) and take the time.
I had a ROCK running with OS / Roon DB on a small SSD and media on a spinning drive, and it ran really well.
I use my Elite desk HP 800g3. It is over 8 years old and carries all you would expect of a computer for normal use. I have 16 gigs of current DDR4 ram / virtual memory and an SSD Hard drive connected with 2 Terabyte memory for Roon Library. I use an identical computer connected to my network as a remote sometimes. Plus my phone. It’s flawless and operates exactly as “they say” on the tin. I have two streaming devices with the ability to have two music sources running through ROON at the same time. But usually only use one. I have used a Mac mini and it to works plug and play no issues. The Roon system is very good and does not require Ultra Tech to work. Whether ROON sounds better with the Nucleus and its clear benefits will be something for another day.