IMO a release workflow would be better with something like this:

1) Upload all files in a staging state. Can be done asynchronously via multiple build hosts. Files in this state are referenced via their cryptographic checksums (e.g. SHA, Blake, etc)

2) Make visible with a single call by providing a manifest with checksums for all source dists/wheels contained in the release. All artifacts are made visible atomically and the release is immutable.

That allows authors to prepare uploads over however many days they need to coordinate hardware, but doesn’t allow for users to discover a release in a partial state.