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!