I had to set the playback speed to 1.5x to get the narration back to a more comfortable cadence. Puzzled why it was so slow? Maybe speak at a more natural pace in future videos? Or did something go wrong in editing/production?
Past IOQM papers should be available online. Get as many solved problems as you can (from any olympiad or qualifier) and work through them. Whenever you can, attempt problems without looking at hints. Get the book "Problem Solving Strategies" by Arthur Engel, it's a massive collection of competition problems with explanations.