In the new editor, I cannot find any way to change a table's properties so that it's width is set by its contents. In the "classic" Confluence page editor, there was an option to select Fixed width or Responsive. I could create a wonderfully small table for things like short text values. Now, I am forced to have a giant table no matter what I do.
As a workaround, I can put a table into a set of 3 columns but that's messy.