My two cents:
for your backhand, you can use some serious leg movements. You were simply moving your elbow. Yes you bent your knees but you did not unbent it on the way into looping that backspin.
Forehand, it seems that you do use some legs into the ball. So that's good.
Timing is everything in table tennis. Every person I talk to, in order to learn loop, should learn to loop with the ball on the way down. Let me put it this way. What is the point of loop? It is to pull the ball up and impart spin on the ball. So why would you learn to loop while the ball is on the way up? If the ball is on the way up, then you either block or flip the ball. You would not "loop" the ball.
Anyway, with plastic balls, the ball loses a lot of spin. So as the ball rises and then peaks and then goes down, the ball actually loses a lot of spin along the way. Therefore it is a good habit to learn how to loop the ball as the ball descends.
Once you get that loop down, then you loop the ball at the peak. Then finally if you are very ambitious you can loop the ball on the way up, almost over the table. But many players reach good levels just by looping backspin balls on the way down or at their peak.
I loop the ball on the way down in doubles a lot because in doubles, there are four people taking turns imparting spins on the ball. Sometimes I really have a hard time judging the spin on the ball and I simply wait..wait...wait..and then loop the ball on the way down. That's pretty much it.