Use YouTube Premium, one may say!

The problem is that you likely don't want to log in the kid's device to your own Google account (with premium activated). If you want to create another account just for that, you need to lie about the age, and need to link a credit card to pay for the account — and for anything else on YouTube, then.

It would be great to have kid-specific accounts with parental control and access limitations; MS provides something similar.