Thanks @Borek but I don't have a YT account.I can be wrong, but I don't think PF accepts videos, it accepts media links to sites like youtube (so if you upload your video to YT you will be able to post it here using embedded media player).
For format conversion and repacking I am using ffmpeg (command line and often tricky) and avidemux. Both free, neither perfect.
That didn't work either. I give up.It used to be that the whole 2-factor login security was optional. That may still be true, that you can decline 2-factor (2-step) security and use only username and password instead. But you may need to look in the fine print to find it, they prefer that everyone use 2-factor.
A 'dumb' phone could work for verification if you have one, as long as it can accept text messages and as long as your plan includes text messaging.