As a general response because there's no video showing your backhand, it's all in the footwork and how you set up for the ball. Biggest mistakes I see is players getting to the ball just in time thus not establishing a solid base with their feet which will create more shot options for you including stepping into it more and transferring weight forward if that's your intention.
Take a look at how you're setting up for the ball. On the forehand it's easier because the player can get a bit lazy yet still get a decent outcome on the shot. Backhand be it single or two handed handed has to be a bit more precise especially with your footwork.
Throughout your life advance daily, becoming more skillful than yesterday, more skillful than today. This is never-ending. - Hagakure