I'm building now my first course and Udemy is my primary target platform.
However, it might that with time I'll consider publishing also on another platform, who knows what the future will bring, what should I know to ensure my content/video fits most platforms? I refer to things like resolution, length, formats or anything that might prevent deployment flexibility
I am not sure there is anything you need to do that is in addition to what you should do to create a quality course. Lectures should not exceed ten minutes, better three to five; resolution should be 1080p, etc.