Had a hard time enabling developer mode. When pressing “About Smarthing” for several seconds nothing happened and the setting screen jumped up an down. Finally I found a trick, use two fingers to press this option and then remove one after a few seconds. It worked after 2 tries. also the description says go to “dashboard” . it should say go to “Smartthings settings”
Not sure if you had seen this page: SmartThings Developers | Documentation
This describes the “long press”, which is what I believe you achieved with your two-finger approach.