[nawtacawp]

R715 might be a bit overkill. I use a RPI with docker. One container with vpn server and one container with pi hole. The pi hole container is not accessible outside the local LAN. The VPN server is configured to use it as a DNS server. I use iOS devices and just use the on demand function for cellular/WiFi VPN (always on). I have an iPhone X and I don’t notice a degraded user experience in regards to the battery.

   13:20:52 up 10:57,  1 user,  load average: 0.00, 0.03, 0.00

I just restarted it 11 hours ago, but the load is never high for the two containers. Currently free -m is reporting 114/927 used

[tomschlick]

It's not bare metal, I have Xen Server running with quite a few VMs so PiHole is just a small chunk.