As of feedback I would consider having collapsed all the threads on the first read of messages and the after reading the whole message user can dig down (like on confluence a little bit)
Thanks! This is a totally valid feedback. I agree it can get very messy when showing everything by default.
Since we have a button to go to next unread message in a discussion that also expands whatever needs to expanded to show the unread message automatically (but doesn’t make the expansion permanent, so on next page load it will still be collapsed), I think it makes sense to collapse by default