Quite a few people use a thirdparty “dashboard” for this situation. You can limit these so that a particular phone/tablet only has control Of a specific set of devices. That way one kid can’t turn off the lights in the other kid’s room, for example. 
or, as you note, delete or edit the routines you’ve set up.
These typically have a free trial or a limited free tier so you can check them out and see if you like them.
The two most popular are ActionTiles and SharpTools. Both allow you to customize multiple dashboards and have different features and functions.
You will still use the smartthings app yourself for administrative functions, but many people like the dashboards for day-to-day control.
Both of these are browser-based, so they will work on any device that has Internet access.
ActionTiles:
SharpTools:
You can find lots of discussion in the forum about both of these, as well as some of the ones that community members have built for themselves. Here’s one thread from last year that compared a number of the options. (The topic title is a clickable link.)
It would be great if smartthings would offer rolebased access controls in the official features, but so far they just haven’t. 