what youâre wanting is quite close to the script Iâm using right now⊠edited slightly as Iâve got a plugin that allows me to group soundtracks and Various Artists separately, and also changed the Various Artist folder name to match your current one.
sorry about the weird formatting, as Iâm adjusting it, the formatting helps me keep things straight. 
$if(
$eq(
%musicbrainz_albumartistid%,
89ad4ac3-39f7-470e-963a-56509c546377
),
[Various Artists],
$firstalphachar(
$if2(
%albumartistsort%,
%artistsort%,
%albumartist%,
%artist%
),
1-9
)
/
$if2(
%albumartist%,
%artist%
)
)
/
$if(
%date%,
\($left(
%date%,
4
)\)
)
$if(
$ne(
%album%,
[non-album tracks]
),
%album%$if(
%_releasecomment%,
\(%_releasecomment%\),
)
/,
)
$if(
$gt(
%totaldiscs%,
1
),
%discnumber%-,
)
$if(
$and(
%albumartist%,
%tracknumber%
),
$num(
%tracknumber%,
2
) ,
)
%title%
$if(
%_multiartist%,
- %artist%,
)
For the letter folders, itâll use the sort-name of an artist first, or the artist name if it doesnât have a sort-name, favoring album artist over track artist, therefore ABBA, Bryan Adams, and The Angels should all end up under A. Also, if thereâs multiple artists on an album, itâll add the artist after the track title. Any artists that start with anything non-alphabetical, (numbers, symbols, and emoji, for instance) will be put in â1-9â. If youâve got any [non-album tracks], itâll put those music files in the artist folder. Lastly, if thereâs a disambiguation on your release, itâll add that in parentheses after the album title.
my script doesnât separate into discs, but it does handle multiple discs as part of the track number, (i.e. âRadio Ga Gaâ on disc 2, track 3 would be rendered as â2-03 Radio Ga Ga.mp3â). it could easily be changed to add separate disc folders if youâd like, either in the artist folder or the release (album) folder.
some actual examples from my collection, notes in {brackets}:
- [Various Artists] {I use a â#â at the start, but you can use a different character if you want}
- (1999) The MatrixⶠMusic From the Motion Picture (Parental Advisory)
- 01 Rock Is Dead - Marilyn Manson.mp3 {multiple artist release}
- 02 Spybreak! (Short One) - Propellerheads.mp3
- 03 Bad Blood - Ministry.mp3
- âŠ
- 1-9
- 4 Non Blondes
- (1992) Bigger, Better, Faster, More!
- âŠ
- 03 Whatâs Up.mp3 {single artist release}
- âŠ
- A
- ABBA
- (2008) GoldⶠGreatest Hits
- Bryan Adams
- (2014) Reckless (mastered for iTunes) {a couple examples of the disambiguation I mentioned}
- 06 Summer of â69 - Bryan Adams.m4a
- The Angels
- (1963) My Boyfriendâs Back (stereo)
- 01 My Boyfriendâs Back.mp3
- âŠcontinues to Z
sorry for the lack of comments in the script itself⊠Iâm still adjusting it at this time, but it works like a dream for me~ lemme know if you have any questions~
edit: I did just remember, I have had âfeat.â artists outside the main artist folder in a couple cases, but thatâs only when there is no album artist/release.
also, if youâve got artists with different scripts, it should sort them properly too, for example Hatsune Miku (in my library as âćéłăăŻâ) will be under H, not 1-9.