Some background: I have a Synology NAS already with plenty of space on it. It runs my Jellyfin server in a docker container. I also have a Raspberry Pi 3b running Pihole.
I would like to get a mini PC to run Proxmox on, and migrate those workloads over to it, as well as use it to host any other fun projects that can be virtualized that catch my eye. It'll also be a useful learning experience as I would like to learn Proxmox to potentially broaden my skills at work, where we are an entirely VMware house, but the shit Broadcom has been pulling since taking over has put a shadow over all of that.
Anyway, I'm thinking I would like something along these lines:
A relatively recent CPU with decent performance and low power consumption. I prefer AMD these days.
Capacity for at least 32GB of RAM, but it doesn't have to have that much from the get-go.
NVMe storage, 512GB or so.
Two ethernet ports. 1Gb is acceptable, 2.5Gb would be nice, though.
Low-ish costs. I don't need this thing to be able to play games or anything, just run my VMs at a decent clip without burning too much power.
Transcoding performance isn't a huge deal either as the Jellyfin server isn't shared with anyone outside the house, and my playback devices so far have been able to play pretty much anything I've thrown at them natively.
I think that I would plan to have the actual VMs stored on a share on the NAS rather than having them live directly on the PC.
I got a few HP Elitedesk/Prodesk computers. One with an i5 9500T for ~200€, a couple with i5 6500t for about 100€ each (one small factor, the other a bit larger, with a PCI slot for a GPU). Not the most recent or powerful, but more than Enough for a homelab with a handful of VMs. Power consumption sits around 36-50w for the 3 machines, a small dlink switch and a Synology NAS with 4 drives.
Yeah, this is my recommendation. I have a cluster of 6 little Lenovo Thinkcenters of varying ages. Some of them have been about the price of an rPi too.
Update: I wound up getting one of the Chinese mini PCs from Amazon. $300+tax got me a Ryzen 7 5700U, 32GB of RAM, 1TB NVMe storage, and a single 2.5Gb ethernet port. I can add a second interface via USB-C if necessary. Really not bad at all. I have Proxmox up and running on it already, with PiHole and Jellyfin already running in LXC containers. Jellyfin took a bit of screwing around to get the CIFS shares from my NAS and hardware-accelerated transcoding going, but everything works now!