What is the ruling on one who finds within himself that he is a polytheist or an infidel when performing an act or uttering a word, so he performs ghusl and pronounces the two testimonies repeatedly (2-3 times daily), and this leads to his inability to pray for two full days?

We advise turning away from obsessive thoughts and occupying oneself with what is beneficial, avoiding isolation, seeking refuge with Allah from Satan when experiencing corrupt whisperings, persevering in prayers and obligatory duties, strengthening faith, and gaining understanding of what contradicts it. Your awareness of the seriousness of what you are experiencing is an indication of your faith, and you are not required to perform ghusl (definition) (ritual bath) due to these whisperings.