I've been building and self-hosting my own analytics platform[0] for 13+ years and never had any major issues with it.

The advantage is that if I do want a specific feature, I can just add it, and I am never worried about subscription limits or surprise charged, because I host it on a fixed-cost VPS.

Things don't really need maintenance and don't really break by themselves, the only time when they can sometimes break is when changing things.

You do need to have a proper setup though, for stuff like disk space alerts, knowing the common gotchas of disabling settings that can cause issues, etc.

[0]: https://uxwizz.com