Allow child to text parent even after messages time limit is reached

I want my child to have a time limit for messaging but also be able to message me even after they reach the app time limit? I've tried everything. How do I do this? I know how to let them text me after downtime, but not if they've reach the time limit for the messaging app. Also, when she sends me a request for more time for any app, I want her to be able to text me the reason she needs more time, but if she's reached her texting time limit, she can't text me. I know I can just put "always allow" for texting but then she spends hours all day texting her friends and I definitely don't want that.