I found the problem only occurs if the document is saved in .docx format. If you save as Word 97–2004 Document (.doc) there is no typing delay
This is very strange: as I wrote in my previous post, my feeling is exactly the opposite!
On my MacBook the problem is more present in files where "Compatibility mode" is shown in the title bar, i.e. .doc files and .docx files saved with compatibility option active.
I can say, for sure, that in some cases I had the problem with a "compatibility mode" file, I saved it as standard .docx, and the problem disappeared.
But anyway based on my tests the issue is not limited to that.
I have some files with a not-basic layout, long tables etc., where typing is very slow even in docx format.
I also tried starting my Mac in safe/clean mode but the problem remained, so it's not caused by background apps.
It's true that draft mode speeds up typing quite a lot, but then we're going back 20 years before real WYSIWYG was here... it's not a solution.