I'd love to see a button with "collapses" a comment and all answers to that comment as it makes navigating comment sections with lots or big answers much easier.
Reddit has a very good implementation of that feature. On Reddit, you can collapse a comment by clicking on the marking the thread depth.
I've created Chrome extension to collapse comment threads (in review for cws)
If you would like to check and give feedback: https://github.com/mcavdar/collapse-ih-comments/raw/main/collapse-comments.crx
Edit:
It's in store now: https://chrome.google.com/webstore/detail/collapse-ih-comments/jmgnbkfmjcnfdjembjpgfokiombkdpfg?hl=en&authuser=0