How can I set effective Screen Time limits on iPad?

Have been attempting to get screentime limits to actually work on the kids ipads for weeks now, have set an app limit to 1 hour 30 per day yet consistently it just doesnt kick in and the kids can be on there for 2+ hours with no reminders or lock out happening.

From what i have seen online this is a bug that has been happening for years...how have apple not sorted this out? At this point im tempted to just get rid of the ipads and get an android based tablet that has a timer that actually works.

[Re-Titled by Moderator]