One thing that seems to have helped (anecdote of 1) is getting a longer (quality) HDMI cable and making sure the end that connects to the MacBook goes in as str

One thing that seems to have helped (anecdote of 1) is getting a longer (quality) HDMI cable and making sure the end that connects to the MacBook goes in as straight as possible. As you may have noticed, there is quite a bit of play in that connector and I suspect having it at an angle degrades the connection.