I run OPNsense on a Sophos SG 230 with some upgrades and deployed a Sophos SG 135 running OPNsense at my dads house last weekend.

Edit: without Zenarmor, the Sophos SG 135 can easily push > 1 GBit/s across networks.

Haven’t looked into Vyos yet.

It really depends. I’ve seen PCs that use nonstandard parts just so you must use original parts, and systems which made use of new things like 12 volt only PSU really early and had great designs for easy access in a compact machine.

I use 1 port for management net without vlan, one for WAN and four as a LAG group for all my vlans to go to my switch.

My plex Container has four Cores and 2 GB RAM. Works fine with just one Core transcoding 1080p24 HEVC.

(Ryzen 7 5700G)

To where did you measure the ping? With such a low latency, it almost sounds like a speedtest within your providers network, which can differ a lot from real world experience on game servers outside your providers network.

Even dns.google and one.one.one.one give me about 5ms advantage to any game server.

Nginx proxy manager, Heimdall Dashboard, Hedgedoc, Your Spotify, pwpush, unifi controller, dmarc reporting tools, zammad and vailtwarden.

I did that with a TP-Link RE655 WiFi repeater which has a LAN Port. Worked surprisingly well and I could even run some servers behind that setup.

Get a used PC, haswell or newer. Those can be found for less than 50 €. Upgrade it to 16 gb ram, install proxmox.

Setting up my own OPNsense router, setting up my own mail server (testing in homelab, then moved to DC as production), Univention Corporate Server as active directory for centralized authentication.