Yes if try press to write it do what video shows sometimes works but sometimes apears if try write nothing written interesting if someone with SwiftKey try works or not for him. I use Note 20 ultra...
That only happens with the Android Central app, or does it also happen with other apps? Can you test a different keyboard app to see if the same thing happens?
That's an old bug with the Android Central app. Sometimes if you click again inside the Reply box it will work, but not always. It usually works fine if you Reply directly to some post but, again, not always.
I strongly recommend you to use the Android Central Forums app instead.