Not sure I fully agree. Even when they played other people’s music it sounded like the Beatles and they had their own sound. Certainly by the time Meet the Beatles hit the US in 1964 they had created a new style of music that was new and fresh.
That was my first exposure to them starting with watching them live on the Ed Sullivan show. They owned the music industry back then and triggered creation of a lot of bands trying to sound like them. There hasn’t been anything like it since. I do regret not finding a way to see them live but then I was pretty young.
I was was lucky enough to see them live as a teenager in 1966 just before they quit touring.