I think it would be more helpful to see you hitting actual balls with a full swing. It's pretty easy to go through a semi correct motion in practice, than go out and butcher the shot on the court. I'm not saying you are doing that, either purposfully, or unintentionally, but it happens.
I will say a couple things based on this vid. Your follow through should be a bit longer and lower, with the racquet handle ending up below the hip, around the knees, rather than under your left arm. That might get more of the effort of hitting the ball where it should be, you upper body rather than more around the shoulders. Your foot work looks abit confused, or unbalanced. It looks like you aren't going through the ball toward your intended target enough. You should be finishing with your back foot stepping into the court forward, not swinging around as much as it is.
Other than that it looks like you have the basic idea, but again, whether you actually use those motions when hitting the ball is another question. I can say with certainty that the motions I go through when miming a backhand are not what happens on the court. I hit perfect backhands everytime in my living room
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