Either just auto-generate them with a service (can even use YouTube as someone mentioned), ask for the community to add subtitles, or hire transcribers if you’re willing to pay
Can re-show the videos one at a time when subtitles are added rather than immediately doing it to the full batch.
You could even just move the site to a Youtube channel, as youtube provides subtitles.
Besides getting around this, having subtitles or a transcription of your videos actually makes them more useful. My hearing is 100% fine but I find that subtitles make me absorb the information better.
I get that this is a PITA, and I agree that subtitles shouldn’t be required. But if you really want your site/videos to stay up it shouldn’t be that hard to just add the subtitles