I suspect my teen is using incognito mode to hide browsing activity, but I’m not sure if there’s a way to see that history from my own device.
Yeah this is a super common parent concern — short answer is no app can grab incognito history remotely without something already installed on the kid’s device first.
If you can get the phone in hand for like 5 minutes, something like Bark or Google Family Link can monitor browsing going forward (they work at the DNS/network level, so incognito doesn’t really help the kid hide much). Honestly the easiest move is just setting up router-level filtering (Circle or your router’s parental controls) since that catches all traffic regardless of browser mode.