For monitoring servers: Zabbix would work.
For APM across some popular stacks: Apache Skywalking might be worth a look (though probably with PostgreSQL instead of ElasticSearch).
For analytics: Matomo is good.
For uptime monitoring: Uptime Kuma is really good.
Consider a separate cheap VPS for the monitoring stack, whatever it might end up being, like something from Hetzner.
Poor man's dashboard: Get your desired metrics with grep/wc/whatever shell commands from your logs, and visualize with PyQtGraph/PySide (or even gnuplot, for an even lighter experience).
Or you can use GoAccess [0]
interesting
> GoAccess is written in C
I assumed it would be written in Golang from the name.
Check out Coroot, it is rather light, simple to deploy and understand
Grafana doesn't take up gigabytes unless you're doing something crazy; it's about 100mb in my small business deployments. Which still might be too much for your $6 VPS! I would still highly recommend Prometheus, as it's native dashboard has gotten a lot better with 3.0
I would love to know the answer? I wonder if Prometheus and Grafana would work at this light level of compute?