So, on Pro+:
- Artists sorts correctly on PlexAmp for Windows (latest version) but does not on Wiim on Android (2.11.7), using Plex (beta) music source and sort by Title.
- Albums kind of sorts correctly on PlexAmp and Wiim when sort by is Artist on Wiim, albeit differently. I think PlexAmp is using Album Artist, whilst Wiim is using Artist... Wiim only offers Artist, PlexAmp only offers Album Artist.
- ... when sort by is changed to Title, PlexAmp works. Wiim does not.
Don't think it's supposed to, so working as expected, I cannot select Wiim as a source from PlexAmp.
Starting to think this was a rushed release. Ticket logged with Support.