Signal has consistently been a pain to use for my moderately sized (<15) friend group chat and for 1-on-1 threads too.
Messages sometimes don't arrive or arrive out of ordered and appear in the wrong order, scrolling up has random jumping behavior, opening the chat in iOS causes my audio to stop playing, there is explicitly no way to back up any of the chat, copying multiple messages is broken on desktop, search is super slow and search result previews have been corrupted for as long as I can remember, sharing links through the iOS share menu causes the app to behave super weird or just crash (my mom can't share links with me through Signal), you can't mute conversations on desktop (IIRC there have been two PRs implementing this feature in the last 2 years; both not pulled), mutual verification is so frustrating that I literally got yelled at when trying to explain it to my parents, I sometimes can't take pictures from within the app, when I can take pictures the viewfinder is half the resolution of the actual camera and everything looks blurry, the most recent app update causes a several second lag whenever I open the group chat, and I am throughly convinced that every issue I've mentioned is so low priority for the people running the show that they won't get fixed for a very long time. At least we have stickers now.
Seriously though I believe in what Signal is doing and will probably continue to use and suggest the app. But it will hurt every time I do it.