Kinda seems like the author found a working solution- public email, aka a forum:
> One thing I instituted that helped was a specific Teams channel called Knowledge Transfer. Any questions that would normally have been DM’d to me could be posted there, publicly for all to see. In theory, others could step up to answer these. I could also forward DMs there to respond to publicly or refuse to answer in DM and require them to retype their question in the Knowledge Transfer channel. Rarely did others step up to answer, but it became more like a SoFuckingAgile office hours, which was still a big improvement.
You also gloss over the fact that he addressed this in the article (things were documented, people just kept coming to him anyway).