By default, when you first open a course with Show only one section per page, it does show all the topics - until you select one. So the only thing I can suggest is instead of embedding the videos directly on the course page, to embed them into Moodle Pages - although of course you might well say that is one extra click and isn't as attractive - but maybe others will have a better idea.
General help
Moodle 372 - How to make "show one topic at a time" work
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