@ChrisG This is a subject on which there is real research. Check the references in this https://community.udemy.com/t5/First-time-Course-Creation/Lecture-Effectiveness-The-Research/m-p/141....
I used to live on corporate workshops. Even when live, people don't want to sit through a three hour lecture. I am sure your video can be cut down into sections that are maybe fifteen minutes at the most. No one is going to watch a three hour video.
I try to keep them under ten minutes. It is a bit hard to cover many subjects in 3-6 minutes. But, the research says.... you lose attention over that time.
None other than upload size limit.
I would recommend staying between 3-8 minutes and not going above 10-12 minutes, at that point student interest starts dropping off.
IF you have long videos/topics, you can do part 1, part 2, part 3 etc.