@Whitebunnyflock
I don't think you can depend on the router only to prevent adult content but is a good place to start. For example, I recently found out if your child uses Discord they can subscribe to adult channels. DNS on your router won't block that. Parents are fighting an uphill battle when it comes to adult content and children.
I would suggest using Cleanbrowsing.org DNS servers because they are definitely better than OpenDNS right now. They provide Google and YouTube safe search by default.
I do not have any financial or other interest in Cleanbrowsing. I am a parent like you.