I predict that the ending is going to have both nezuko and tanjiro die in the end at this point every pillar is dead with maybe one or two might live, but they will be able to take down muzan with tanjiro giving the killing blow but his death comes afterwards, he succumbs to wounds finally able to join in his afterlife with family with nezuko as well.
This is how I see this ending all in bittersweet kind of ending