I got a Ryzen 7 5800H with 32gb of ram and a 1tb hard drive for 320€... I don't have the dual on board nic, but beside that, it's quite great cpu wise with Proxmox — multiple VM on it, doing transcoding, DNS, dealing with download and search, Home Assistant. Of course transcoding 4k live is costly, but that's an exception. I can use NVMe and SATA hd, that's nice.

And I can update the ram and use ECC.

Not bad all in all !

Still, I got a Dell SFF with an I5 and 16gb of ram for less than 100€ — updated it with a 4 2,5gbps NIC, will be good for OPnsense... If I don't switch to a Melanox Connect 3.