I'm using opnsense with Toob on a fw4b which has a j3160 cpu and 16GB RAM. With this I have a couple of wireguard and tailscale connections and it doesn't seem to struggle at all, I get full 900/900 (only around 500 on wireguard however, this seems to be a cpu limitation). I'm not running IDS or anything like that and never intended to so my performance requirements were low. The thing I really like about the fw4b is its low power usage, it idles around 6w and peaks at 8w. My whole nas/media/firewall/cctv setup uses around 45w idle and 60w peak.
My old Pondesk E3845 as it my parents handling their toob connection with a pfsense CE instance. They barely use the network and are on the standard CG-NAT/IPV6 package. S2S VPN back to my pfsense box.
My XG35 Rev3 is around 20w and my XG230 Rev2 is about 30w, upto 50w if I fit the 10Gb fibre module. Both have pfsense plus license on them, but the X230 Rev2 only has IPsec-MB Crypto, which is fine. I've swapped the CPU from a G4400 to an i3-6100T.
Will decide which to keep. I've got a XG125 Rev 3 too, that's got pfsense 2.7.2 on it, but will put opnsense / XG Home on it to have a look again before probably selling off. I've explored Opnsense before, but just couldn't get on with UI, so I switched back to pfsense. XG Home has positives again, I prefer the firewall rule structure on that, but there isn't let's encrypt or wireguard, so I'd have to host them on something else, which isn't a prob as I have a Dell PowerEdge T340 running vMware ESXi 8 (need to switch to something else).
My power usage tbh is far too much.
Both the XG135 and XG230 are in a rack in the loft, gets a bit warm, but kit handled it so far.
I'll have a look at the ionos VPS, many thanks. I was going to look at tailscale at some point, haven't looked at that all, so don't know the suitability. However I expect by the time I factor anything like that, just pay the £8..