Offline Android Screen Keyword Detector

I need an Android-only utility that quietly watches whichever app screen I choose and alerts me the moment a word, phrase, symbol, or emoji I have entered appears anywhere on that screen. The content could be part of a photo, a running video, a PDF, chat text—anything visible to the eye... (Budget: ₹600 - ₹1500 INR, Jobs: Android, Android App Development, Android SDK, Java, Mobile App Development, Mobile Development, OCR, Software Architecture)