I’m in the same boat. My poor HC-2 is struggling on memory running Omada (WAP controller) and HomeBridge, among other things. I use Emby so I don’t need transcoding - supports 4k streaming just fine.
Right now I’m looking at one of the fanless Intel four port software routers, like this one.. But for a machine like that I’m going to use ProxMox to spin up a Firewall/Router/VPN/Networking VM - not sure which OS/image. That will remain separate from my media and web serving. I will probably end up just off-loading the network tasks to the new machine, and leave my HC-2 running as a media server. That way I can restart and upgrade the systems independently. Using ProxMox, it may be possible to move the media services onto a second VM on the same machine, but I’m not sure what advantage that might give me, if any.