Thank you so much, fren.
I had just navigated to Adobe Express right before I came and saw this comment.
I have a full-service subscription and use only the Acrobat Pro DC feature (without using the Document Cloud because Adobe doesn't need a stash of my research).
Never knew it might be able to strip audio from a video, so I'll give it a shot.
FWIW, I came up with another idea. If worst comes to worst, I'll just play the video in "mute" mode on my screen tonight, after I clock outta Night Shift, and then I'll trim the extra if I sleep longer than the 3 hours and 12 minutes that the video will run.
I learned something from this little problem: FACEBOOK IS RECORDING US.
How do I know?
Because I was screen recording someone's Facebook page on Saturday.
Juicy stuff.
It took me three hours.
When I played the resultant video back, I could here my dog barking in the background, and I heard my own voice talking into my phone because I had been making comments in my Signal app while scrolling.
So I've since disabled the "microphone" on my laptop, but let that be a lesson to us all.
Facebook is recording us, for sure, otherwise how did the noises being made in real life get picked up while I was screen-recording my scroll through a Bad Guy's Facebook page?