Lampworth 

Lampworth is a free app for iPhone and iPad that sets calm, clear screen-time rules for your family. Choose up to ten apps, decide when they rest (school time, homework, bedtime) and add a daily limit if you want one. Your child can see the rules. No account, no ads, and nothing leaves the device.

Short videos for parents: setting up, bedtime, homework time, and what to do when your child asks for more time.

Made in the United Kingdom.
https://lampworth.com