ActionTiles would be an outstanding option. You can create a custom panel for her with only the SmartThings devices you want to give her access to, including an SHM Tile for arming/disarming, plus you can give her visibility to other devices, but if pressed, requires a pin code. With ActionTiles, you very rarely ever need to go into the SmartThings app.
You could have different panels, one for you with everything displayed, and then a very restricted panel that she accesses on her phone (SHM, Door Locks, a couple of Routines) from the browser and a shortcut on her phone.
They do charge for the product, but you can install and try it out for a couple of weeks for free before you make a decision. It’s how I access and operate ST 95% of the time.
