Don't change who you are for an interview. It will just result in a job where you aren't happy being a different version of yourself. I know it is frustrating to not find work, but finding work that isn't right for you brings whole new levels of frustration later.
And, as others have said... this rejection might have nothing to do with you. If they had 1000 applications, and you were their choice above 998 of them, you still get the rejection because they hired the person who was above 999 of them.
And, as others have said... this rejection might have nothing to do with you. If they had 1000 applications, and you were their choice above 998 of them, you still get the rejection because they hired the person who was above 999 of them.