This is a comment not a question.
Android produces an MPEG-4 ( MP-4) which "can be tricky" to convert from landscape to portrait, or vice versa.
A video recorded on an Android device and uploaded to "files" ...."takes a while" but it does, indeed, upload, this on a cable with supposedly "high speed". It takes, for this user, about the same time that it takes to heat a cup of water in a microwave for coffee.
The telltale is that one sees a "grey film image" when it is uploading and then the first "frame" of the video.
It seems to go in "two parts", the blue progress line appears about half completed and then sits for a while and then "jumps" and the video is uploaded.
The file can then be linked in "modules".
When first clicked a "semi-transparent black mask" appears and a message to the effect that the video, in landscape mode, is being converted. No mention of that to which it is being converted, but it does, indeed convert to portrait.
The video appears "narrowed" and plays very well.
As an aside, this conversion is no "mean feat", I have dealt with the frustration of fiddling with conversion of one to the other using a variety of software on both Linux and Windows(tm). So, my kudos to the developers.
I do not know that this needs any "comment" but if a moderator thinks that it better fits in the questions section and that it should be moved and the title should be changed to something like "how do I..." I hereby give permission to so do.