If you wish to keep your sanity whilst removing/adjusting lights in this lesson, you MUST disable auto-exposure in the project settings…I’m amiss as to the instructor failing to mention this most VITAL setting…
You don’t have to disable it and in fact shouldn’t. It can cause issues moving from a dark environment to a light one, but this is actually like real life - if you’ve ever moved into a darkened area, your eyes take time to adjust and similar moving out of one into a light area. You would never have a consistent light level between the two and eyes adjust to these levels, which auto exposure deals with. Turning it off means all your light levels have to be dealt with by you manually. If you find them too extreme, you can adjust the settings for postprocessing to reduce the level of auto exposure if needed - I think this is in the postprocessing volume.
As for why it isn’t covered in the course, lighting and postprocessing is so extensive you could probably create a course just on this topic alone. The aim of this course is mainly camera use and the sequencer. While you could argue that lighting is a key part of camera use, for the most part the defaults are fine. Sometimes they need adjusting when you’re dealing with indoors however which is probably what you’re finding.