Stackoverflow is one of the most useful websites online imo and I think it would be great to be able to mark comments as the one that solved your issue and also have the ability to “follow” a post and/or comment thread so you get notifications on updates to a post or comment you didn’t post.
If you can find documentation on how they do it I would appreciate you sharing it so we can show to the lemmy devs to simplify their work if they decide to implement it.