Aside from NVDA's table navigation keys (control+alt+arrows), Word includes some of its own:

alt+home (move to first cell in row)
alt+end (move to first last in row)
alt+page up (move to first cell in column)
alt+page down (move to last cell in column)

Plus, add SHIFT to select (eg alt+home then alt+shift+end to select current row)

also alt+shift+up to select the row above and alt+shift+down arrow to select the row below (I probably wouldn't recommend these as if you are already in the top or bottom row they actually separate that row from the rest of the table - which is arguably even more important to know when you've done it).

Pressing any of these keys results in the cursor moving as expected, but NVDA does not announce anything.