Thanks for the suggestion. I don’t think that a delay is appropriate at this level. This NodeMCU project is just a very simple interface from your sensors and alarm to SmartThings. A delay for entry/exit really should be a feature of the SmartApp that triggers the alarm. This is where all the logic is.
An entry/exit delay definitely appears to be a commonly asked for feature of Smart Home Monitor. See here: Smart home monitor exit/enter delay
Also if you search these forums for “Smart Home Monitor delay” you’ll find a number of workarounds that people have been using. My position is that this project should remain just a simple device interface.