The bigger problem with HA and integration is the security side. IFTTT is great but what testing is done to ensure the system is secure. Also its totally cloud dependent. Without it the automation's wont work.
Im a big fan of HA and use home assistant to control all my automation's. None are cloud dependant (apart from alexa commands as I currently have no choice) but heating, security, lighing etc is all local.
If interfaced my HKC hybrid system to my HA instance using ESP32. This is a 1 way (by design) communication. My HA instance has no possible control of the security in any way.
I use my alarm as 'presence' detection, ie its the only bit of kit in the house that knows when everyone is out, in bed or in.
Triggers for full set will put the house into eco mode, turn off all devices that can be lower the temps of the rooms etc.
I also use the movement detectors to alter comfort heating temps of the bedrooms based on if they are used in the last 24 hours.
But only approved HKC products can arm or disarm my system, so keypads, keyfobs or apps.
There is no way any HA part can be compromised that could unset my system. I also use dualpath coms for the app so when i lose internet connectivity it use a monitored gsm.
A lot of the diy / smart systems require the cloud to operate. 'If' power was cut or lines cut etc these systems become inoperative until connectivity is restored. Completely useless IMHO