The release/album you’ve mentioned has listed “Frida” as its artist – though Plex will be using the artist’s main name.
As for the release/album types… same here: Plex follows the categorization of primary/secondary release type of MB. You can try to convince the community at MB that their categorization is wrong or disable the album type categorization inside Plex (Settings > [Server Name] > Library > Group albums by type → Disabled)
I can see that Plex will not be my upnp server, if it can’t keep to the IDv2/3 tags then it’s not really much use for people who collect music (or takes tagging seriously).
I’ll just continue to use minimserver, not a big issue, I had just hoped that I could cut down on the number of moving parts.
If your embedded tags are in good shape, you can configure Plex to prefer them. I don’t think this will affect the album type issue, since I don’t think there’s an ID3 tag for that.