Why is there no option to manually control subtitles on the TV app?

Any normal viewer, hell, even crappy 20 year old media boxes, have a button that lets you select from the available subtitles in a file.

I've got some anime for which the "smart" subtitles decide I need Chinese captions. And there's literally no way of turning them off short of disabling all subtitles in the global settings.

It's such a rudimentary feature that I feel like I surely must be missing something, but from a fairly comprehensive search I really don't see what. Nearest thing I found was an option to map a subtitles button, but it doesn't accept any inputs and therefore doesn't work.

So that's what it boils down to? Is this just horrible design? Or what am I missing?