The following is a summary of a discussion that just happened on IRC channel and stopped about https://chatlogs.metabrainz.org/brainzbot/metabrainz/msg/4384091/

For example, let say you want to get the most relevant artist to the song "Over the rainbow". Website work search makes it pretty clear it is Judy Garland: https://beta.musicbrainz.org/search?query=Over+the+rainbow&type=work&limit=25&method=indexed

However, there does not seem to be an easy way to get this information through the web service version 2:

• Work search https://beta.musicbrainz.org/ws/2/work?query=Over+the+rainbow
  doesn't include interpreters
• Work lookup with related recordings https://beta.musicbrainz.org/ws/2/work/f8217125-b460-3902-8903-82979e3785ee?inc=recording-rels
  doesn't include interpreters even though recording relationships are included,
  and there are too many recordings here to allow querying web service for all of these just to deduce the most frequent artist.
  Note: there is no recordings subquery for work lookup either.
• Artists browse for a given work https://beta.musicbrainz.org/ws/2/artist?work=f8217125-b460-3902-8903-82979e3785ee
  doesn’t sort artists by frequency,
  and there are too many artists here (406) to accept them all as most relevant.
• Recordings browse for a given work is not supported yet, see MBS-10124.