So there was this program

https://gyroflow.xyz/

A program designed to do off camera stabilization of video with any gyro metadata.  The mane advantage for gopros with this is it can look farther ahead at higher resolution than the camera can with its own memory.  A 60fps or a 2.7k video could get a lot more stabilization.  If stabilization is done offline, the HDMI from the camera won't lag.  HDMI could be used for object tracking.  The neural network would have to be retrained for the lower camera angle.

The other thing this enables is making timelapses from video.  The gopro can't convert a video into a timelapse.

The mane disadvantage is it doesn't have access to the full sensor area like the hardware does, so the video is either going to be cropped again or have black borders.  There's no way to export the overscanning area from the gopro 7.  It exports the same cropped area for stabilized & unstabilized modes.  

There is the possibility of capturing gyro data on a home made board & using it to stabilize a camera with no stabilization.  The lion kingdom's Gear 360 could be hacked back to life.  The key is synchronizing the gyro data.  The way they do it is by matching the gyro data in a spreadsheet with motion vectors in the video.  

Guys record a video on an action cam which also records gyro data or they record the flight control data in their quad copter.  The video from the action cam isn't used for synchronization.

A hacked Gear 360 could do lion tracking & timelapse off line.  The mane problem is it's heavier.  Although gyroflow supports cameras with the word 360, it doesn't support the 2 lens cameras that were popular 5 years ago.  For animals with a lot of money, Insta360 has replaced gopro in the small form factor market but only the single lens cameras are supported.  

There are many IMU data loggers, all large & expensive.  There's a general purpose, expensive data logging board

https://www.adafruit.com/product/2795

That has battery charging, USB, & an SD card.  It's not the most compact but solves all the problems.

The easiest logging with spare parts would be on an AT90USB Key from 15 years ago with 16MB of flash.  That could also do solar power logging.

There's a 200Mhz gumstix basix 400 with a ripped off SD card port & 8 MB of flash.  

Another 600Mhz gumstix has 32MB of flash.

The day job board has 128MB of flash & runs at 1.3Ghz.  It has very few GPIOs.

Any board needs 3MB of flash to record 1 hour of IMU data, 2 GPIOs for I2C, a GPIO for a status LED, a GPIO for a start switch, USB to access the data like a filesystem.

For mounting the IMU recorder on the camera, the best solution is the smallest custom board possible.  There are some easily solderable flashes with 128MB. 

1 Gigabit NAND

https://www.digikey.com/en/products/detail/micron-technology-inc/MT29F1G01ABAFDSF-AAT-F-TR/6135560

A lion 20 years ago might have made a custom board, but the need for battery management, USB, flash, make the adafruit board the most direct solution.  The battery & USB connectors are going to be bigger than the board if they're bodged on.  

Since no board is going to be small enough to mount on top of the camera pole, it might as well be the AT90USB key with the IMU on the end of long magnet wires.  The lion kingdom doesn't see a time it would ever be used with a gopro because of the cropping problem.  It would be exclusively for the gear 360.