Greasy Fork is available in English.
Allows you to download subtitles from Amazon Video
< Valutazione su Amazon Video - subtitle downloader
Works fine for me. Opened your link, clicked on "Download subs for this season" and got a subs.zip file with 237 subs. Are you sure you don't have some other extension or script that conflicts with mine?
subtitle download fail for multiple Amazon series exammple https://www.primevideo.com/detail/0KN67W36HIVTRF6TU2TTRWZS2A/
it is always stuck when the download process is almost finished