You can never be the best at everything.
You will look and work hard and hard, and there will be those people that you will see that are better than you, or at least how you perceive them to be. You will look at their work and believe you are inefficient and perhaps maybe you will work harder. In years and years time, your work will be much better than the work of these people, and you will look at their work and you will know it's that much better, but do you know what you will actually do? You will look at other peoples work, people who are still better than you, and you will STILL think your work is bad.
My point is, that a lot of the time you compare only to those that are better, if this motivates you then for sure go ahead, but if it demotivates you that's bad. Remember, you are most likely a better artist than a lot of people, but you look at the people who seem to be a better artist than you and you FORGET about everyone else, all the people (like me) who simply don't draw anything beyond stick figures. You need to put things in perspective and realize your art isn't bad, it's not the best, but only one person out of 7,000,000,000 can be the best and guess what? With things like art, beauty is in the eye of the beholder. Maybe one day, you'll find one person who thinks your art is the best art in the world, and tbh, that's all you really need for your art to be considered amazing.