Everyone else has described the complications that a Mac mini would have. So why not consider something else? Lenovo, HP, and Dell make 1l ultra small form factor PCs and they’re pretty cheap on eBay. They’re also low power. Search for Tiny Mini Micro to find information.

I have three Lenovo Thinkcentre machines - two with 32gb RAM and one with 64gb RAM - running my Proxmox VE cluster. Highly recommend using those small machines instead of a Mac mini.

Why are those patch cables so long?!

Risking sounding like a broken record, I always suggest Tiny/Mini/Micro 1L form factor office PCs. Lenovo, Dell, and HP all create ultra small office PCs that make great low power servers. A Pi will use 5-9w at idle, while these PCs will use 11-13w idle. They also use more standard components such as NVME drives, 2.5" drives, and replaceable RAM. Easy to find under $100 USD used, I’m sure you can find them under 100 euro.

Look up 1L mini PCs - Dell, Lenovo, and HP have similar one liter mini PCs that would’ve been used as a lightweight frontend in offices. They are easy to find on eBay and can be pretty cheap.

For example, my lab at home consists of three Lenovo Thinkcentre tiny machines. I bought them off eBay for $60-80 USD. They each came with a 500gb HDD and 8gb RAM. I have since upgraded them all to a 500gb NVME, 500gb SSD (they have a 2.5" drive bay), and 32gb of RAM. They run as a Proxmox VE cluster.

I think I might have $500 USD into the entire setup, including my 10" wide rack enclosure.