I just tested, and yes on desktop there is an 'Auto-translate' option, even for videos with 'auto-generated captions'. However on mobile (YouTube app on Android

I just tested, and yes on desktop there is an 'Auto-translate' option, even for videos with 'auto-generated captions'. However on mobile (YouTube app on Android, Firefox, Chrome) and my TV the 'Auto-translate' option is missing, so I can only view the generated subtitles in the original language. I mostly watch on mobile or TV, so :-/