As I see it, in this video you just posted, after the first several points of the first game, you play decently. When you loop with your BH for most of the match, there are many places where your loop has too much spin for him to return.
When you have trouble with your BH, there seem to me to be a few categories:
1) You are tentative so you push.
2) You don't move your feet but you move your racket to the ball and are taking a bad shot from out of position.
3) You rush the shot.
Often there is a combination of 2 and 3 where you are out of position and rush the shot as well.
Those shots where you are trying to hit a BH on a ball that was hit to your elbow, those are just going to be weak shots even if they go on. On those, you sort of need to commit to the BH and move to the ball. Or you need to turn to your FH on those shots at your switching point. And that is a good habit to get into.
There are also a few shots where the ball is hit to your FH and you respond to move over and take the ball with your BH while aiming down the line towards the opponent's FH. On a few of those, you move part of the way to the ball, but need one more half step and that is why you miss it.
The ones where you are reaching to the wide BH without moving your feet (there are not as many of those) you can't get your power into those either. The step would not be a big movement. But you would be helped by training the habit of moving to each ball.
Your BH has almost as much trouble handling the long pushes to the BH as the serves. It seems like you are not as prepared for that outcome as maybe you should be.
But, still, when you are in position and hit your BH, it has very nice spin.
Multiball 2 point drill where you take the BH wide and middle and go back and forth so you one-step wide and then you one-step to the middle over and over would help. Doing the same drill with the FH on the FH side would also help. Shadow drills of that would also help.
With the receive of serve, part of what is happening is that you are not moving before the serve so you are not moving when the serve comes to you. So you are caught with your feet sort of glued to the ground. There was one point where he caught you with a serve wide to your FH. I think it was a gettable serve. You just didn't move your feet till way too late.
So, when your opponent is tossing the ball for the serve, your feet should actually already be moving, not going anywhere, but not glued to the ground. I think that may be part of why you do not move to the serves.
But it does also happen sometimes in the rallies. But you can move. You just are not in the habit of moving if the ball is close enough to reach. So I have a feeling, training the moving of the feet would really help.
And doing a lot of serve return practice. Over time, those things can go away if you are trying to train the habit of moving. If you just play matches, you won't be able to work on those things the same way while trying to win points. So, it just means a certain amount of training would be really helpful to your game.