Agree with
Please take the following to heart but not with offense, you will be much better off in the long run if you do: you are making the mistake a lot of beginners make which is that you are trying to loop before you've even learned how to do a basic forehand drive/hit/counter. You do not need to worry about looping fast much less looping at all yet probably. If you only are getting 60-70% on the table when hitting slow you need to drastically get those percentages up before worrying about hitting with spin or power.
You have issues with your stroke but rather than having too many people telling you that you need to do this or that with your arms, hips, whatever, you will be able to work most of it out yourself by practicing your basic forehand drive and getting the percentages up. The reason you miss your shots is because as soon as your racket gets to the ball your arm and wrist start moving in different directions because you haven't grooved the feeling of actually just hitting the ball solidly and getting it to move forward. Your paddle is moving upwards, sideways, downwards at the actual point of contact rather than steadily through the ball.
I agree with this. I also think, a lot of what you need is practice and confidence. Every stroke you take, you are doing something different at the contact of the ball. It might be worthwhile finding a robot you can use and doing thousands upon thousands of simple counterhit and drive shots. A lot of what is going wrong is that you don't have strokes that have been grooved into muscle memory so, after every mistake, you are overadjusting based on the last miss rather than adjusting to the incoming ball.
The biggest issue is the amount of time grooving the basic shots so you have a solid stroke in muscle memory. Rather than making weird adjustments to something when what you thought happened and what happened are not the same thing.
Each screenshot is from one stroke except one.
Please note how different your finishing position is on the first and second shots:
And again for the third shot:
The next two photos are from the same shot:
What happened that your racket is facing up?

And the last one.
A note, if you wanted to see what you were doing, filming from behind you totally blocks the stroke and the contact.
But you can see that you are doing funny things with your wrist and forearm in the middle of the stroke, directly on contact as ThePongCommenter alluded to.
This is because you need to do thousands of the same stroke to groove it into muscle memory in order to get consistent and solid. Those weird spasms (adjustments) to your arm as you are about to contact the ball are simply a sign that you need to repeat a good basic counterhit stroke and a drive stroke for 100s of 1000s of times before you are solid.
So, the end result, it is simply that you need to do the repetitions. No single thing you are doing in your stroke is the issue. It is the confidence in contacting the ball and having a solid stroke already under your belt. Those last moment adjustments that are causing you to do strange things with your racket are simply from you needing the repetitions.
I don't like robots for many things. But here, a decent robot might be useful to give you the repetitions. I don't think either you or your training partner are solid enough to give you thousands of quality balls in a row to get you to feel the contact more solidly. But it is not that you are doing anything wrong. It is that your reflexes are forcing you to change things because you don't have the repetitions under your belt yet.
So, practice, practice, practice.
And props for posting footage. It is good to post footage on the forum. Thank you. And don't worry about the issues. They will go away if you do the repetitions.