We have an old Galaxy that grandchildren use for play. No SIM card, but on wifi. The Google account previously used is obsolete, so we can't sign in. But without signing in, the "play store" won't let us get to the list of apps to delete them. And some of them need root to delete, and I don't want it rooted.
We'd like to delete things like the entire contact list, the list of calls and transcribed voicemails, facebook messenger stuff, etc. Nothing to hide, as the saying goes, but no need to have curious little ones reading about deceased relatives, other peoples' phone numbers, things their parents did as kids, or questions on child-rearing. :-). Or unintentionally tapping a name and sending an e-mail.
The method that I used on the Moto X4 that I lost in Spain a year ago for deleting messages doesn't work here.
If we reset to factory settings, all the games disappear too, and we'd have to log in to a valid account to get them back.