You can long tap on the username of the thread you want to hide. It was not the most intuitive thing for me but I found it accidentally and maybe I can save you from the searching!
That behavior is about to change. There’s already a jerboa update available that changes the thread-hiding trigger from long-tap on the comment header to regular-tap on the comment body (away from links and other tappable bits of the comment).
This update is available on f-droid now, but only came out yesterday I think. Might not be on the play store yet, but get ready for this to change on you.
I hope they add an option to swap the long and short press actions. I’ve found myself accidentally tapping and collapsing a ton of comments today.
Feel free to post a feature request: https://github.com/dessalines/jerboa/issues/new/choose
This update is available on f-droid now, but only came out yesterday I think. Might not be on the play store yet, but get ready for this to change on you.
Better yet, get your apps straight from the source by using Obtainium to manage app updates from GitHub. Not sure why I don’t see this talked about more. https://github.com/ImranR98/Obtainium