I am using premium Flatsome theme from Themeforest but I heard that there are themes using UX or Elementor Pro is better or has better advantages. is that true? What is the best page builder for Wordpress?
Elementor Pro is fairly popular.
Divi would probably be the most popular.
To my untrained eye, they all seem pretty similar. What's wrong with the theme you bought that you want to switch to one using Elementor?