I have similar comments to everyone who has posted observations and suggestions.
I stress first what I like.
My first comment is I like what you do with the lower body and core. You are not on back of feet, the use short step adjustments to get imposition, you start it off with the leg and hip.
I also like that you get mostly into position and command the strike zone. You do not appear to be hitting the ball way too in front of the optimal strike zone like many adult beginners.
These two things I mentioned, your short light steps and good enough position, (along with striking the ball in effective part of strike zone) should you carry these through your growth, it will help you out a lot.
What I do not see happening (like others have already noted) is an efficient coordination of the parts of your body to make a whip to get your pace and spin. The very first vid and pretty much the next, you are hitting with maybe 15% power if that, so it is difficult to do that given what looks like the objective of a slow ball controlled.
The first vid, you look like you are in 4x4 drive mode where your entire core and upper body and arm all move together like they are locked in place. That does not help the good lower body work you start out with.
What you need to discover for yourself is how to stay loose and independently activate the different parts and pieces in sequence all relaxed and firm it right at impact to make an efficient whip. I could describe it in agonizing minute detail, but when you go to try doing it, that stuff will not make enough sense for you to get your limbs to do the things needed.
A good whip has the body be loose, start some motion (like you do with your legs and hip), then with each step, channel and amplify it. If you have a part be tight (often, for men, it is the back of the shoulder) then you are killing off and dissipating that kinetic energy. That is the basic mistake many do to sap their power (and also control). When someone tightens up something out of place and early, the player has to re-generate it again, often with just the upper body. No matter how Mr. Universe one is there, it is not gunna happen efficiently after you tighten something up too early.
It will come down to how you can sense how your energy got created, and how you can channel and amplify it in steps in sequence.
The number one thing I observe adults do when trying to make power is to tighten the muscles behind their shoulders and try to power the ball with them. All that does is stop the existing energy and now the player has to try to make power quickly and forcibly from a position way too high and to control that torque, the player slows something down or tightens something else to counter balance... result is always a fail in power, spin and consistency.
The number two thing I see adults do is lock their hip and torso. The idea is the player wants to use the waist to generate power... but they are actually doing is stopping their energy and trying to quickly torque their way to power. The body simply does not have it to torque 2/3 of its mass from rest locked together to produce enough explosion to make the bat go fast enough with any control.
The number three thing I see players do is death grip the bat too early. When you firm up, you do not death grip it, but it is a very sudden tightening at the right final moment. When a player tightens the grip too soo, it stops all the kinetic energy from flowing down the upper and lower arm. Then the player tries to compensate with shoulder and it fails.
The keys to a whip are relaxed body with initial movement generated and each step channeling and amplifying the energy and delivering it to the ball firming up right at impact with the grip.
I put extra emphasis on INDEPENDENT and IN SEQUENCE and RELAXED and WELL TIMED and especially the concept that it is much easier to accelerate something already in motion than something at that is at rest - especially if there is more mass involved. Simple physics tell you that you need exponentially WAY more power to do that to something that is heavier (like say your entire upper body if you lock it up together).
These are the basic conceptual things one must know about a whip and it is up to each individual to learn how to apply the concepts and make their body function. There are individual differences that allow an athlete to use a part more or use it less and still produce a result. However, the whip being comprised of putting something in motion and accelerating it by a sequence of independent timed explosions with a firming up at the moment of impact - that remains the way to deliver power to a ball, whether that is spin, spin and speed, or raw speed. That is effected by how solid you strike the ball and how and when you firm up.
When one comments about the stroke ending up to far in front and little chance to recover is basically a player striking the ball too far in front using too much torque - that makes a player follow through way in front and is difficult to stop and reset.
Kim Jung Hoon on his basic FH champions more waist rotation in preparation. What is effective about this is that a lot of the explosion and movement before impact happens a little earlier. The benefit of that is you get a lot of power generated... and now the waist is also used better, and the waist before impact is now turned and the center of the impact zone is in its "normal" place... but the explosive torque and movement is already done... and the impact happens and now there is mostly just the mass of the lower arm going through the zone... the waist is already preparing to reset and it is not used much or at all to slow down the arm and anything else getting too far in front... so it is real easy to stop the arm and reset. The majority of the torque happened while the body was on balance and had leverage... so there is little force to tip you over as when you do it later and more to the front.
If a player tries to use more waist without prepping some rotation a little earlier, then the impact of the ball happens more in front of the zone (or is still forcibly torqueing during and after impact) and it is harder to control direction of ball. it is also much more inherently difficult to stop all the torque and mass that is now more forward (or still going after the shot) and get it back. Simple physics.
These are a few things to think about and discover how your body can be relaxed and make the explosions happen on time in sequence to have you channel and amplify the possible power you can produce. Think, how did Bruce Lee being such a relatively small dude be able to deliver such devastating power to a target? There are whip and impact dynamics going on that can be learned and applied.