I have 3 smoke detectors of this model and with this modified dth from the original zigbee smoke detector it works very well and detects smoke correctly.
It works independently and with the app and sends notifications well, it also integrates well with STHM.
It sends status every 3 minutes and the battery after 9 months is still 100%.
Once the alarm is triggered, it only stops if the smoke level drops or the reset button is physically pressed on the detector and if the smoke level remains high, it triggers again.
The alarm cannot be stopped from the app.
In automations you can use the alarm event to activate other complementary actions