Is niyyat for ghsul needed?

Everytime I do ghsul for janaabat I sit in the bathtub and keep repeating the niyyat in my heart and it take me around an a hour to be fully satisfied with my niyyat... (I think I'm kind of having OCD idk) so can I leave niyyat and just start with bismillah and carry on with ghsul as usual. When I'm done my brain it's so stressed. Please answer me I need the answer very urgent