Whaddya know? Uploading an Instagram video with an Android 7-based phone is fine if it’s on a Chinese OS and not a western one.
This was a bug I wrote about nearly two years ago, and I wasn’t alone. Others had difficulties with their Android 7 phones with getting Instagram videos to play smoothly: the frame rate was incredibly poor. The general solution posted then was to upgrade to Android 8.
I never did that. Instead I would Bluetooth the files over to my old Meizu M2 Note (running Android 5), and upload to Instagram through that. It wasn’t efficient, and soon afterwards I stopped. By 2020 I gave up Instagramming regularly altogether.
With my switch over to a Meizu Chinese OS (Flyme 188.8.131.52A, which on the M6 Note is still Android 7-based) earlier this week, I uploaded one video and it appears to be perfectly fine.
So all those who wrote on to Reddit and elsewhere with their Android 7 problems, this could be a solution—though I know it won’t appeal to those who aren’t familiar with the Chinese language and would rather not get lost on their own phones. Those who managed to upgrade their OSs have likely already done so.