I have an energy monitor and Home Assistant
it's pretty neat, and I can verify that the energy usage is essentially the same on both. Helps to pinpoint electricity drains, as I can tell what breaker is using the juice (the smart plugs are also helpful here).
I went with the Emporia Vue2 which unfortunately requires some tinkering to get it to run local-only, but once I set that up it's been a dream. Too bad they don't offer it out of the box configured for local use...
Another fun trick you can play is to use a private IP on your public DNS records. This is useful for Jellyfin on Chromecast for instance
it uses 8.8.8.8 for DNS lookup (and ignores your router settings), so it wants a fully qualified domain name. But it has no problem accessing local hosts, so long as it's from 8.8.8.8's record.