In many draft/briefing presentations I see, there is a page 1 that was inserted after the full presentation was finished. It contains the things the presenter really wants to say.

Do not feel guilty to discard almost the entire presentation (slides 2-50), take page 1 as a story board to build up the entire presentation from scratch, focussing just on the things you really want to say.

The three weeks of work you invested in page 2-50 where necessary to get you to write page 1, which you can now turn into a full presentation in less than a day, because the full picture is crystal clear, very different from where you were 3 weeks ago.