Well one of them anyway, but not "the" movie of the year as there have been better movies than Joker that have been released in 2019 - Once Upon a Time in Hollywood, Honey Boy, The Peanut Butter Falcon, American Woman, Arctic, Blinded by the Light, Missing Link, Luce, The Lighthouse, Dolemite Is My Name, Ash is Purest White, Parasite, The Farewell, An Elephant Sitting Still, Monos, Shadow, and then there's A Beautiful Day in the Neighborhood and The Irishman which are out soon and getting great buzz left and right. I figure you have not seen any of the aforementioned movies and have no interest in the last two probably.
As far as Avengers: Endgame winning Best Movie is concerned, dude it's the E! network's People's Choice Awards not the Academy Awards, these types of award shows are based entirely on entertainment value and popularity not artistic merit. As far as crowd pleasers go it is hard to argue against Avengers: Endgame given how much success it had at the box office and in merchandise sales of course it was going to win from the list of nominees. Joker, while a great movie and well-liked(it is the most profitable comic based film ever based on its small budget compared to most others in the marketplace) but it's not a film everyone can see and enjoy, it is a very dark and at times very disturbing picture that you will not see whole families want to hit play on during gatherings.