What I look for is, 128GB RAM minimum, decent number of PCIe lanes because I want two fast NVMe drives, a HBA card ( though this I guess could be external ), two network ports minimum, ZFS, sane terminal, native support for containers and VMs. Native support for UPS interfacing, native support for backup of containers and VMs. And lastly a community of other users doing the same.

Dual power supplies is a nice to have.

So you are sad that the Mac mini isn't a bog standard HPE/Dell/etc Server?

Boy will you be pissed when you find out about laptops, phones, game consoles and basically every other compute form factor.

Might want to look into rackable Mac Pros though!