Most of my stuff lives on a cheap hetzner vps so that power is someone else’s problem lol. at home it’s a raspberry pi that’s always on (a few watts) and a bitaxe miner doing about 19W, that’s around 14 kWh a month, like 3 euros here. the gaming pc is the only hungry thing and it stays off, the pi wakes it with wake-on-lan when I actually need it. took me a while to get the bios settings right (erp off, power on by pci-e) but it was worth it.
I’d add backup age and size, not just status, like alert if the newest dump is older than ~26h or smaller than 1MB, a job can say success and still leave you a useless file. and disk fill with a threshold, not only the graph. learned that one the hard way, a table on my vps was getting a row every minute with no cleanup and one day the disk hit 100% and postgres just died for like 40 min, obviously nobody was looking at the dashboard right then lol. now 80% warns and 90% sends me an email, and uptime kuma checks the cert expiry from outside. I guess the dashboard is nice to look at but the stuff that matters should ping you
for a multiplayer browser game I ended up skipping websockets and using SSE for everything that goes server to client, and plain POST requests for the actions. it’s just http so the reverse proxy, cookies and reconnects work without doing anything special, and EventSource reconnects by itself. one gotcha if you use express with compression middleware, exclude the SSE route or the events get buffered and arrive in chunks. websockets make more sense if the client sends a lot, mine mostly listens