Migrating fields between subgraphs

I am using Apollo Gateway with fully managed federation and currently one of my subgraph is much bigger than the others and has very very minimal Apollo federation support.
I want to break up this monolith but I can’t have downtime and I also need an easy rollback. Ideally the legacy part of the monolith and the new subgraph(s) will leave side by side and i could switch from Apollo studio from new to legacy, back and forth.

I am not sure whats involved here, is there a documentation / blog explaining this process?

Also in a recent blog article (Announcing Apollo Federation 2 - Apollo GraphQL Blog), i can read :

There’s a lot we’re adding in the coming months:

New directives that support a stronger source of truth, field migration across subgraphs, and type merging that can be relaxed even further

Should I wait?

Just found a lot of docs I should have been aware before asking the question!!