I want to pause app limits for just one app
You can only delete app limits and not pause it.
To delete the usage limit for an app, on the 'Limited Apps' page, tap on the desired app, and tap on ‘Delete Limit’

I want to increase/decrease app limits
On the 'Limited Apps' page, tap on the desired app, make changes to the limits, and save it.

I want to block the app during a routine
On the 'Limited Apps' page, choose your desired app, tap on the ‘This app is allowed only during’ section, select or deselect the routines to allow or block the app during those routines, and don’t forget to save it!