In the new app, the only way to arm/disarm the Smart Home Monitor feature (which is a completely different feature from the one in the classic app, it just happens to have the same name ) Is based on the time of day or by doing it manually through the app. You can no longer do it with Geopresence. You also cannot unlock locks through an automation.
Routines are now just automations and folded in with all the other automations. Others can speak more to those details.