The specials as well as season 1 will air on BBC One in the UK and on Disney+ internationally on the same day, probably even simultaneously.

I'll follow this with a few quotes from production info, network of the bible:

Simulcast and rebroadcast
As a general rule, only the primary network. No network airing reruns.

The network field should be used for the very first network. Multiple networks should only be added when new episodes first air on a different network or when the series is originally broadcast at the exact same time on two or more local networks.

International co-production
Two or more networks can be added when the series is broadcast simultaneously in the original language AND a) the countries are equal producing partners or b) international networks have a producing or "in association with" credit in the original credits.

In the context of international broadcast with time difference (e.g. US/UK), simultaneously is defined as broadcast the same day.

I think that last passage likely applies here. For the first passage to apply we'd have to wait and see what happens.

Here is the original BBC & Disney+ cooperation announcement for reference:
https://www.bbc.co.uk/mediacentre/2022/doctor-who-bbc-and-disney-branded-television