Is it possible to add the option to configure the sensitivity via matter natively instead of needing an aqara hub ?
I think there are 2 different question here: hub requirement vs app requirement.
I checked the manual and it says joining via Matter just needs “a hub/gateway that supports the Matter protocol” so I don’t think it needs to be an Aqara hub. Any Matter border router works for pairing.
For the sensitivy question, manual describes adjusting it as done “through the app” both times it’s mentioned, no native Matter attribute for it. Even on Matter you’d likely still need the app once to touch sensitivity. Zero-app fallback is Zigbee through an Aqara hub. Sounds like a good feature request though.
That depends on which mode (Open/Close Monitoring Mode or Object Monitoring Mode) you want to use.
Since Object Monitoring Mode is only available via Zigbee, you can, of course, only adjust the sensitivity there.
In Open/Close Monitoring Mode, you can adjust the sensitivity in the Aqara Home app. For third-party Matter platforms, it just depends on whether or not they support this feature.
Image Source: Aqara Multi-State Sensor P100: Detect Object/Door/Window Status
Therefore, an Aqara hub is not absolutely necessary for adjusting the sensitivity, either via Thread or Zigbee.
For example, this can be done using a Zigbee coordinator in Home Assistant via Zigbee2MQTT.
It’s also important to note:
The Camera Hub G5 Pro, Camera G2H Pro, Camera Hub G350, Camera Hub G410, and presumably older hubs do not support the P100 currently via Zigbee.

