A super simple flight computer that entails only breakout boards mounted directly to the av bay.
Example parts:
Microcontroller - https://www.digikey.com/en/products/detail/stmicroelectronics/NUCLEO-G431RB/10231584 (or a Teensy 4 for $5 more, but staying in the STM32 family makes it easier to port SPICA code)
IMU - https://www.adafruit.com/product/4634
Altimeter - https://www.adafruit.com/product/1893
GPS - https://www.adafruit.com/product/746
XBee (this would need a custom breakout board PCB, or use a different transmitter) - https://www.digikey.com/en/products/detail/digi/XBP9X-DMRS-001/5972743
The above would cost $185 total, with $106 of that being the XBee which could be swapped with a much cheaper transmitter.
Just an idea if we don't have the resources to make custom PCBs. The above could also go on a perf board.
If we need deployments those could be handled by relays on separate batteries.