I always found SO really slow. Often I would get stuck on something, ask a question and then have to wait an hour for a response (which would often become a back and forth of comments with large periods of time between them). Even on discords for less popular languages/libraries you generally get an answer in minutes.
I think this is likely due to the incentives SO creates. I have never actually answered a SO question because it feels like you need to answer perfectly or get torn apart. I will often contribute to a discord question even if I don't full know the answer just because I think I can add something useful.