Translation by pickedaxe on Twitter. They allowed me to share the subtitles file, which I've uploaded to 4shared for better privacy.
Do note that this is timed for the MagicStar-subs torrent of the movie. I'm not sure of the linking etiquette, so please contact me privately on Twitter or Bluesky for a link.
To use this file, you'll need VLC Media Player. Put it in the same folder as your torrent (it will replace the Japanese subs file - simply rename the JP one if you want to keep it), and playing the .mkv file should open it automatically with the subs!
If it doesn't show the subs, just right click anywhere in VLC, then go to Subtitle > Add Subtitle File, and select it.