As far as I know, you should start (in a copy of the
document) by "freezing" the outline numbers:

You can run a one-line macro.  If you've never used VBA
before, I suggest practicing this in a non-important
document first.

From just a general part of the document (nothing
selected), go Tools / Macro / Visual Basic Editor

Click in the window down low called "Immediate"

Type this exactly:
ActiveDocument.ConvertNumbersToText

then press Enter

(You may notice that, as you type, a balloon of options
pops up.  You can double-click on "ConvertNumbersToText"
and that will help, but you still have to press Enter to
activate it.)

It'll seem like nothing has happened ... but ...
Go File / Close and Return to Microsoft Word

and you'll see the numbers are manual.

One more thing:  if you used toolbar numbers (not attached
to styles) for the auto numbers, you're done.

But if you used Styles such as Headings 1 thru 9, those
style names still are attached.  You should apply a
different style, such as Normal, to the affected
paragraphs.
* * *
The next step is to convert the text to a two-column
table, separating columns by tabs.  This will work well if
you have a bunch of consecutive numbered paragraphs.

Select them, then Table / Convert text to table
Separate text at tabs    OK

Now maybe adjust column widths a little; then copy the
table and paste into Excel.