I'm honestly a bit mixed on this... I don't think that (especially young) children should have access to explicit, graphic sexual content, especially kink. If you as a parent want your kids to have access, so be it... but then the onus should be on the parent.

On similar lines, I think that something between an unrestricted smart phone and the classic dumb phone is a market segment that is needed.

Phone’s have these settings already. I don’t know if people know how or bother to use them.

https://support.apple.com/en-us/105121