TFA was a fine movie. Of all 3 films, it had the least flaws. That isn’t to say it was perfect (Rey winning the final fight was a huge mistake) but it still did its job well:set up the rest of the movies.
Then Rian decided to ignore almost everything it set up for his own interpretation of his own Star Wars universe, and, well, the balance was lost. ROS was just the crash that started with TLJ.