Which tool/solution(s) do I need for my project?

I will soon launch a mobile application (with a backend) as a solo dev, it's not my first time launching a project, but I have never been good at monitoring hardware resources and backend health. Those are the things (that I think) I need: Hardware monitoring: memory, disk space and CPU usage. Backend: Metrics (e.g. count registration, login, logout...), Logs (e.g. INFO: "User A did this", WARNING "User B name not found") and error traces. Mobile: Metrics, logs and traces. To give you more context, I plan t