You guys make me wish for an open-architecture drone system in which the user could install 3rd party or scratch-built modules to enhance whichever characteristic(s) are desired: range, speed, carrying capacity, fly time, remotely controllable lighting, PA, sound monitoring, etc.
Think of the possibilities!
There are several commercial drone that use PX4.What your referring to is the build yourself FPV drone.
How To Get Started With FPV Drone - The Ultimate Beginner's Guide - Oscar Liang
Learn how to get started with FPV drone in this comprehensive tutorial, covering the basics of building and flying FPV drone, tips on safety, equipment and software.oscarliang.com
I've been exploring something similar with my MA2 as well and came across this:
Mavic Air 2 Payload Release - Simple, Easy & Affordable | Finish-Tackle (finish-tackle.com)
It uses a fiber optic cable triggered by the LED on the bottom of the drone. Might be possible to connect a photoresistor to a Raspberry Pi?