An album is identified by the Album title and also the AlbumArtist, both need to be the same for all tracks in the album.
In your case your album artist is split between Johnann Sebastian Back; Peter Hurford and Peter Hurford and this can be seen by using Browse by Artist/Album
It is standard SongKong to remove composer from albumartist so I would remove Bach from the remaining 81 files in Disc 14, 16 and 17.
Displaying discs is a bit tricky. The preferred MinimServer default approach is to just hide the disc boundaries as they could just be considered an artificial construct, this is most useful when a work traverses two discs but this doesn’t usually happen.
To display disc boundaries just having the DiscNo field completed is not enough for MinimServer, you also need to add something to Disc Subtitle, this can be found on the Discs tab of Manual Edit, the disc subtitle should be different for each disc, and the same for all tracks on each disc. This is explained further in the second part of http://blog.jthink.net/2017/06/minimserver-with-songkong-part10.html
(The first part describes an alternative method that appends something to the album name. But this requires SongKong to be able to automatch the album, and is not compatible with non-minim server players it will cause each disc to be seen as a different album.)
But on checking your data you seem to have already done this so I wonder if the problem is simply due to the albumArtist not being consistent, so it may work after fixing that. If it does not work please post a screenshot showing what happens when you expand the album in your music player.