I have already checked through the existing feature requests and found no duplicates

• Yes

Is this a server-specific feature?

Navidrome

What do you want to be added?

With e.g. for track 1

ALBUMARTIST=St. Lucia
TRACKARTIST=St. Lucia
REMIXER=RAC
REMIXARTIST=RAC

the Navidrome web interface understands the remixer tags and displays the remix artists:

Feishin does not:

One result of this deficiency: tracks an artist remixed do not appear in that artist's Feishin discography.

Please teach Feishin about remixers!