I see a bunch of failed attempts in console to connect to slack websocket. Is everything looking ok for you?

After blocking 2 iframes with adblocker I could finally inspect what was going on :)

Anyway, I can definitely feel that is fast and seamless and worth to give a deeper look! In the meantime, prefetching all the content in docs or source views upon load generates quite a few requests and might explain your scaling issues. Would you mind sharing statistics for number of users and hardware behind ?