What I’m finding is that ST (even on iOS 13.1.x) doesn't work very well.
In particular, I find that even with access supposedly blocked from 7pm to 9am on every day except Saturday (when I limit access to 1 minute, since 0 does not appear possible), access to the following apps does not appear to be properly blocked at times clearly outside of 7pm to 9am period:
This makes no sense to me. Messages is the worst offender. I've tried specifying the apps individually under App Limits (and yes, blocking is checked) and the categories (Social Networking and Entertainment), but it makes no difference!
I've tried disabling Screen Time and reenabling it, but that didn't help. I also reset all settings.
Here are some screenshots: