I self host for years about 30 services, out of these 3 are vital (bitwarden, home assistant and pihole).
I work in IT, I am a geek so I tried a few monitoring systems and wrote two myself.
Then I realized that I have self-sustaining, 24/7 monitoring agents: wife and children.
I gave up trying to have the right stack and just wait for them to yell.
Seriously: it works great and it made me wonder WHY I am trying to monitor. Turns out this is more for the fun, discovery of tools than a real need at home.