I used qustodio to monitor. reliable app.

I feel that at 13, they not only have to be monitored but parents should also be proactive to guide the child about the do and don't. Beside passive, active action is equally important.

Give them a lousier than yours device. Not able to surf freely. Restrict. Controlled.

As far as I know, Android OS does not allow full spy or whatsoever, otherwise its considered a security issue. Big time.

You can however try installing Google Family Link for children & teens

I'm using it right now.

It does control his phone, track his location whereabouts (via the app and Google Map), track his app usage that he installed, set time limit on app and entire phone per day usage, and even limit his Chrome browser. I think this will fit your requirement.
but you cant spy his Whatsapp messages , if he has one. You will need a separate app for that.

The app can able to lock down the phone should he misbehave or the phone is stolen.