Yup, been using slack since 2015, first in the Web app and now in the "native" app and usability and speed have gone downhill in the past years. Focus problems after editing a message, wrong recommandations when typing /call, sluggish edit mode, sluggish recommandations window on /xxxx commands, wysiwyg editor first forced for everyone even though it was buggy, ctrl k getting slower and slower to switch between chats. That's the things in top of my head, I used to love the tool but not so much anymore.

Their support is great and responsive though (I've reported every issues I've encountered)