https://smartsocial.com It has a lot of small articles to learn about different apps and has practical suggestions on how to safely use them. They have 400 recourses and tips!
https://protectyoungeyes.com is great and has a “free home internet assessment”.
www.internetmatters.org is based out of the UK, but it is one of the most thorough websites when it comes to internet monitoring and has very helpful videos and guides on how to use parental control and monitor use. https://www.internetmatters.org/parental-controls/
*Bark has great information about some of the most popular apps kids use and what parents need to know about them. Bark is also a platform that parents can subscribe to that monitors internet and app used across devices. However, their app reviews are free for anyone to look at though. At no point should you be asked to pay! https://www.bark.us/app-reviews/