I haven't seen Avatar since it was in theaters, and I was way late. I saw a regular non-3D showing after it had been out for about 3 months basically just as a way to have a night out with the wife and no kids. As for the race...I become less and less interested as time goes on. Its mildly entertaining to follow though, just because numbers interest me. I myself admit that I'm not contributing since I haven't seen End Game again. I loved it when I saw it, and I'm sure I'll get the BRD eventually.
Besides, Endgame basically already beat Avatar, what Endgame is trying to top now is the money Avatar made in subsequent releases due to the extended cut. It's kind of superfluous anyway, since Disney now owns 7 of the top 10 highest grossing films of all time, including Avatar.
Lastly, I'm an *all or nothing* type. If your #1 in the world, but only #2 in North America, then that isn't a complete victory IMHO. same with TFA which became #1 in NA, but ended up #2 WW (now #3).