Take the bad reviews with a grain of salt. Many grains honestly. For one, there are clearly bots giving one and two-star reviews. Secondly, many one and two-star reviews display pretty childish views, especially those based around "love".
Moving on to the actual movie, I give it an 8.5/10, with my main point of contention being the fight scenes. Quite literally all the fight scenes. Even so, there is much to admire and appreciate with this one. The writing is decent enough, easter eggs that have been sprinkled throughout other MCU movies and series, unsurprisingly, make their way into the movie (which is good), and the mood and tone feel pretty proper throughout. Of all the elements of the movie, I want to give a special shoutout to the amazing CG team working on Dr. Strange. Truly a work of art that most could not even fathom how to accomplish themselves and many take for granted. Easily the best part of the movie. It is worth a watch.