There is a script for auto-linking of recordings to the tracks by Aerozol
https://github.com/Aerozol/metabrainz-userscripts/blob/main/MusicBrainz%20Quick%20Recording%20Match.user.js
and Search by ISRC in release editor by chaban
https://greasyfork.org/en/scripts/549398-musicbrainz-search-by-isrc-in-release-editor
Harmony can use them both to automatically find and link recordings by ISRCs while importing releases
There is a script for auto-linking of recordings to the tracks by Aerozol
https://github.com/Aerozol/metabrainz-userscripts/blob/main/MusicBrainz%20Quick%20Recording%20Match.user.js
and Search by ISRC in release editor by chaban
https://greasyfork.org/en/scripts/549398-musicbrainz-search-by-isrc-in-release-editor
Harmony can use them both to automatically find and link recordings by ISRCs while importing releases