From the posts so far is it a conclusion that raising the shadows of the 5D IV 4-5 stops is not acceptable, but 3 might be.
And
Sony and Nikon are better for astrophotographers.
And
Daniel Browning no longer posts on this forum.

We might go back and look at some of Daniel's complaints about Canon. But if my memory is correct this kind of summed up why we no longer see him posting.