When I was like 13, just starting tennis, I had a weird, but semi-real serve. Then I somehow broke a rib playing tennis and sort of abandoned it.
Since then, I have had a "pancake serve." It is like I am a 12 year old 3.0 level player based on form alone, but it has actually gotten acceptably good. I play D3 college tennis, played top 6 this last year, played disappointingly badly but stayed top 6 all year. Still with a serve like a 6 year old. I had a player (who beat me 6-0 6-1) tell me he'd never seen a pancake serve be as good as mine.
But I do recognize it is not right, and can't get better really. So I am trying to develop an actual serve. I have some coaching from someone who I am actually better than, but who has a real serve. I will try and upload a video of my efforts soon. It's progressed pretty well, allows me to get much more spin and hit a much better second serve but it's still unreliable and double faults infinitely more than the old one. So please help.
I will try and post a video of my new work-in-progress serve tomorrow.
Here is a youtube video of 15 year old me (I am about to turn 19 now) hitting a serve- I will try to find a newer one soon. It, and the rest of my game, has progressed quite a bit since then, but the form sadly isn't much better.
Its mighty hard to change a tennis or any stroke for that matter, you ask a QB who's been playing for more than five years to change his throwing motion from a sidearm to an 'over the top kind of motion and watch him struggle, IT AINT easy! I used to tinker with my serve to the point where I got the serious case of the yips!! I just couldn't release the ball!!, Id stand there on the baseline appearing as if I'm going to serve but I was really mentally telling myself to release the ball, all because I wanted a ' proper serve'. Anyway, I went back to my old motion and focused instead on the basics like the ball toss/placement, e.g. the height and how far in front I wanted the ball and also racket head speed in the throwing action, I still have off days but my serve is solid now. I've seen both your video clips and you have deffo improved the action a bit but it still seems a little rushed and jerky, it may never be as smooth and wrinkle free as Sampras' or Serena Williams but then it again it doesn't need to be exhibit A, former pro Carsten Braasch keep at it though