Can't watch the tournament as I have no subscription, but it sounds like we have a great final on our hands - you can't ever count Djokovic out, but I suspect Sinner will take it.
Djokovic has likely guaranteed his WTF participation with this run; he might not even need to do particularly well in Paris. Remarkable given that he played few tournaments and won no ATP titles so far this year. (I'd be a bit surprised if he ends the year without one, though stranger things have happened.)
A good run at the WTF may keep him in the top 4 and maintain top 4 seeding at the AO.