I’m not sure about this one, but I recently installed LibreNMS (an open source nms) on my home network and it does a decent job keeping track of traffic on my ubiquiti edgerouter. It uses snmp so should work with most routers, I imagine. I specifically set it up to tell me when I use more than a certain amount of data in a day to avoid data caps. It was a bit fiddly to set up, but kind of fun.

Ended up starting to write my own network analysis tool. Most of these tools don’t fit in with “home lab” type networks. Probably should finish it and share it here, might actually fit people’s use cases.

Is it somewhere on GitHub/mind sharing a screenshot?

If you want to drop $12k, maybe.

Zabbix is a good all-rounder.

Zabbix is fabulous.

I've heard good things about Uptime Kuma.