Both services explicitly disallow this by default in their delivery specifications, unfortunately.

Netflix: https://partnerhelp.netflixstudios.com/hc/en-us/articles/215...

> Netflix requires a non-subtitled version of the content. Netflix defines “non-subtitled” as the presence of main titles, end credits, location call-outs, and other supportive/creative text, but no burned-in subtitled dialogue, regardless of the language in the primary video.

Amazon: https://videocentral.amazon.com/support/delivery-experience/...

> Video

> Global packaging requires component asset packages to be delivered with a semi-textless video file that can be localized with discrete subtitles and audio dubbing.

> Also known as “Texted with no subtitles,” “Textless with main, ends, and graphic text,” and “Non-subtitled”, Prime Video defines semi-textless as a video master without burned-in subtitles, regardless of the language.