Back in the Flash SWF days the output was HTML 4. Now it's HTML5 and that is all you should be using. End of story.
There are still some SWF components available in Captivate 2019. But you should NOT be using any Adobe Flash output or SWF components in your courseware now.
And there come Operating systems that still use old, native Software.
Do you think this applies here?
The only problem with software simulations which I sometimes see mentioned is with Full Motion Recording slides. They were originally Flash-based but should be converted to MP4 on publishing to HTML5. That is sometimes failing, not sure why or when.
Pesonally when a FMR slide cannot be avoided, I would stop the simulation recording and capture a Video Demo slide which has not only a better editor than FMR slides but also publishes natively to MP4.
And when you try .MP4, a lot of buffer issues get attached to that same data, it becomes almost impossible to execute a successful mission here.
You seem to misunderstand my comment about replacing the Full Motion Recording slides in a software simulation by Video Demo slides. I am not at all talking about publishing a Captivate project to MP4. Please read carefully what has been written.