UPDATE UPDATE UPDATE!!!
It is possible the immigration officer will not stamp your FMM form and give you back your half. August 2022 INM just started phasing out the paper form. Instead he or she might write something on your passport stamp page - some numbers and the number of days you are valid to stay in Mexico.

I actually got just about everything recorded, saved and edited this time!

100% Recorded with the following:
GoPro Hero10 Black
In the Media Mod
Mounted on and Powered by the GoPro Volta
Audio by the Media Mod (with a mask on and terrible background noise)