I have zero interest in watching a TV show where the main character uses sign language with subtitles. When I'm watching a TV show, I'm not capable of paying enough attention to the bottom of the screen with my eyes for me to notice the subtitles showing up in time to actually read it all. By the time I notice the subtitle popped up and then start reading it, the subtitle goes away before I am able finish reading it. I end up missing half of the dialog. Yeah, sure, I can rewind and watch it again, but that just ruins the flow, pacing, and enjoyment.
Same thing happened to me in the Eternals movie, ruining it.