This is such a huge gap. Why there is no widespread more impromptu collaboration product I have no idea. I try to get people to use the excalidraw shared whiteboard any chance I get, at least that doesn't require the uncomfortable on-camera appearance.
There's got to be some other process we could try to recreate (to the extent possible) that "together" feeling of the office. Maybe set aside an hour when team calls into a meeting but just keep on working as normal? And can banter/ask random questions etc. Otherwise things are just too formal.