Hi, be-useful
Welcome!
I understand your concern regarding the access of subtitles with the Disney+ app on Roku, and I'm here to help.
To access and adjust subtitles on the Disney+ app on your Roku, press the Start (*) button on your Roku remote while watching, then navigate to "Audio & Subtitles" and select your preferred language or captioning option.
If this does not work, it is recommended to reach out to Disney+ support and inquire further for assistance. For more information, you can refer to Disney Plus Channel Support
Hope this information helps, and keep us posted on what you find out.
Thanks,
Roku Community Team.