How to set different time limits for Messenger and Messenger Kids?

I have time limit for my child for the messenger app so we can transition to messenger kids (MK). However the limit on messenger also applies on the MK. I read that it could be because the parental account of MK is the messenger the child is using. So I changed it and restarted the phone. But it still doesnt work. There is no specific MK button for the app limit. Help. I want my child to be able to contact anytime but i also dont want child to use regular messenger.

[Re-Titled by Moderator]

Original Title: messenger limit also messenger kids