There is a forum user here looking at and tinkering with the Doorbell API relating to integrating it with Home Assistant. His posts are a few pages back.
2. If the Button is pressed can i get notifications in homeassistant ? Like a Sensor.
Here using an Elk 930 / 960 doorbell sensor and debounce board which connects to an alarm panel which connects to Home Assistant via an MQTT addon.
Another way is to use a reed switch near the plunger inside of a conventional doorbell and connect this to a Low Voltage firmware (Tasmota or Espurna) WiFi device like a SonOff.
doorbell button wires ==> Elk930/960 ==> Doorbell Chime
====================> 2 wires defined as "doorbell" zone in alarm panel.
The alarm software (OmniLinkBridge) talks MQTT and Samsung Smartthings Hub running in Docker like HA today.
In Home Assistant via MQTT see the following. The circuit boards are tacked next to the doorbell transformer and use a 12VDC supply from the alarm panel.
View attachment 56566