The EAA specifically covers mobile apps in certain areas, while this doesn’t cover all apps, it’s safe to say these categories make up a significant section of mobile apps available. For the most part, both Android & iOS built-in screen readers will do a great job of making the text available for the user, even making guesses at text included in images where needed. Android does provide a High Contrast Text accessibility setting, but unfortunately provides no developer documentation regarding what this does, or how developers can leverage it, so this may require a setting within your app to increase contrast.