Security Scanning Android Phones

Hi folks,
If I am concerned my kid’s phone has been tampered with, [strange SIM error] is there any way/app to scan it for malicious apps, or changes that have been made?

I’m probably overthinking, but want to make sure.

Thanks

SusEpic

Factory reset it?

I use sophos intercept x, it’s free to download, don’t actually know what it does but it keeps telling me it’s scanned stuff 🤣

Factory reset it?

☝️

Thanks for the hints guys.
I’ll try those.
Worried it won’t sort Pegasus spyware apps, but I’m probably overthinking 😜