A lot of discussion in https://community.metabrainz.org/t/handling-name-of-transgender-artist/538657 and other threads led to a general mostly decided stance on how to deal with trans artists and changed names, at least for now, but this hasn't officially been codified in any style guideline yet.

Basically: the artist name should be set to the changed name, recordings and release groups can be changed to the changed name (especially if a re-release has happened under the changed name, even if there's a larger number of releases under the deadname). Releases that were re-released with a changed name as a straight replacement (rather than reissues) should lead to the previous release being marked as withdrawn and a release under the changed name being added. Deadname aliases that were not used as credits should be removed (there's no reason to deadname an artist if the name is not explicitly printed on a release and documenting it). Deadname credits should be kept as printed since they are documenting the existing release (but will point to the artist listed under the changed name).