Well newest interview said they want to make part 3 ending better and more satisfying and moving than the OG
x.com
So theorists about to go wild xd
In my opinion, you shouldn't read too much between the lines.
The end of FF7 OG is pretty bare-bones.
You finish the final battle, see the team leave the crater, wait on the bridge of the ship and then the meteor collides with the LS.
And then a glimpse of the world 500 years later (= the planet isn't destroyed).
Our characters have no conclusion. I think what he's saying is that they're simply going to expose what really happens to our team after the final battle. Like pretty much... every Final Fantasy since FF7.