Same problem here.  I had to reload MSFS 2020 because of program crashes.  After reloading it and re-adding Capt Sim's 777, the vertical speed is inop.  I am very familiar with MS2020, flying it since 2020.  This 777 add-on has been my very best airliner to fly.  I can't use it now because of the vertical speed flaw.  I have already made a post about this but got no response.  If you can find the problem, would appreciate being informed of it.  Good luck.