I'm going to say more than you may want. I watched both of your videos a number of times, asking myself why your swing looked so familiar. Badminton. Yep. The tennis forehand is designed to move a much heavier racket against a relatively heavy ball.
You would simplify things if you adopted one favored stance. I suggest semi-open, the stance in which the line from your right toes to your left-foot toes makes a line 45 degrees to the baseline. Your knees must be bent, flexed, every time. When you set up, have completed your backswing and are ready to begin the forward swing, follow this very quick sequence: Push off with your left foot to shift your weight towards the right sideline. This will cause your right foot to react, lifting your torso into the hit. You'll immediately start rotating your torso. Experiment will let you get the best timing. Old Agassi videos make the thing clear, as do slo mo's of most any pro.
The upper body: Your backward flick of the racket to get lag, your sort of loop, is an artifact of badminton. In tennis you want to turn your UB back taking the racket along with two hands. You want to do this prep early. You are NOT going to want any backward flick or loop when you begin the launch of the forward swing. You can rotate the racket head toward your back, mostly relying on its inertia, relying partly on rotation of your arm or forearm...which aids lag without providing more backward momentum.
You use your off arm, left arm, usefully. That's good. So it's about the right arm and your torso. At the instant you do the footwork described above (quick two-step push up and over with left foot to trigger up-and-forward with the right foot/leg) you (your torso) should be facing the right sideline. At the instant you're rising up powered by your right leg you should be starting the rotation of your torso. The hitting arm should briefly stay behind. Your hitting arm hand should at that moment be at least a foot away from your torso toward the back fence and roughly in line with your side.
So, at the instant of push off (leg launch) you have your off arm swinging right and your racket reaching its low point. At that instant a bunch of things happen at once: You let your upper hitting arm rotate clockwise in the shoulder socket so that the hitting arm can for an instant remain left behind the torso. That rotation will also cause your upper arm to lock a bit in the shoulder socket, so that the rotating torso starts to drag you hitting arm forward, no arm muscle needed at first. You will find the roll of your upper arm moves the racket head back and down, at which motion you'll find the butt-cap of your racket pointing approx. toward the incoming ball. Pull the butt cap toward the ball for an instant, the arm-and-racket being powered forward by your torso rotation, which rotation happens easily because of your launch upward off your right leg. laugh. Don't let your arm take over the motion out to contact until the torso has given the arm good speed/power. It is the key to a reliable big forehand. Pick a few slo mo's and careful "get" the synchronization.
Everything in the preceding paragraph happens almost at once. Watch some slo mo's (I'll link three). Match my words to the video forehands and draw your own conclusions. You can pick up all the bits described above in a few days. Grooving them, of course, takes much longer. In the linked videos Fed's forehands start at about the 9:15 mark. In the Djoko video they start at about 4:20. Nadal's, I vaguely recall, start around 4:15. Note that Nadal's and Fed's forehands are remarkably similar in the essentials aside from flourishes. Djokovic attains very similar racket positions as his swing procedes, but he uses slightly different means to attain them.
Federer
Nadal
Djokovic
This all sounds complicated. It isn't. It is just particular. You won't have any trouble making the transition. Watch the slo mo videos until you get crossed eyes. laugh. When you get the parts described, the whole sequence will happen very fast and easy. Really. I've only offered the words to make what is seen in the videos comprehensible. What they do is not what you currently do, so just make the change.
gotta get stronger I guess ... 
