Currently Online 
S.Peelman on 18 June 2021
I have a hunch that the surface world will 'merely' act as some sort of a hub between the islands in the sky and underground areas, if what we saw in the earlier trailer was indeed underground. So the surface I think is much smaller than in BotW and maybe even made up of corridors (at least in TP overworld style), with a lot of the regions from the first game inaccessible, but it is used to move up or down at places. If you think about it, if the islands rose up from the ground like we see Hyrule Castle do, then those areas don't exist anymore and are, on the surface, now just a big hole or something.
But as how it goes with Zelda theories, this is probably way off.
