I do this. It drove me nuts that SmartThings Smart Home Monitor appdoesn’t come with basic Exit/Entry delays on configurable zones.
I ended up switching to @geko SmartAlarms which can do that easily and works well with Door lock user code management so when I enter in a successful code it executes “I’m Back!” I also use @kevintierney New Zigbee Device (Securifi Key Fob) and programmed in the buttons to be able to Arm/Disarm the system from outside the house and that works well too if you want to keep SHM. I am still playing with both but so far the Key fob is more of a backup because the family likes just entering the code at the door lock.