Another good option is Summarize.ing, which offers immediate and accurate summaries of YouTube videos. Highlights, mind maps and segment-by-segment summaries can help you quickly absorb a lot of information. The service is free, though premium plans are on the way for heavy usage.
If you want something more interactive, check out Video Highlight. The tool not only summarizes videos, but also generates timestamps, transcripts and video outlines. It integrates with Notion for note-taking and has features like smart search and highlighting, so it's good for market research or quick video analysis.