Hey reaper82,
Just a heads up - most of us here have found that the “without them knowing” approach usually backfires eventually. Kids are way smarter about tech than we give them credit for, and when they find out (and they do), the trust thing gets messy.
I tried the stealth route early on after my divorce and it blew up in my face. Now I just tell my kid straight up that certain apps are monitored when she’s at her mom’s place or mine. She grumbles but at least she knows the deal.
If you’re set on monitoring Instagram specifically, most of the apps here (including eyeZy) can track DMs and posts, but honestly? Having the “here are the rules, here’s how we’re staying safe” conversation first saves a lot of headaches later.
Just my two cents from someone who learned the hard way.