I’ll take the liberty of linking your video for everyone’s convenience, ‘cuz I had to hunt it down.
A favorite guitarist of mine, Jacky Vincent, put up a video on this subject just a couple of days ago. His video is probably better than all other videos that you might have seen, so go watch it. In fact, I’ll put it here. Watch it here.
Here are my thoughts:
First, the technique is easier if you’re relaxed. It’s easy to get tense and frustrated because this is a bizarre and tricky technique that is super fucking weird to learn, so every once in a while take a couple deep breaths and let your muscles get soft.
Second, you said something like this: “people tell me you need to lightly touch it with your thumb as you go by.” That’s a reasonable description of what happens, but it would be a fucking nightmare to try to learn the technique if that’s how you think about it. Don’t overthink it. Hit the string with your thumb and the pick at basically the same time. Don’t even stress about exactly where on your thumb the string hits, just start whacking away. In the future, after you are able to comfortably do pinch harmonics, then you can start refining your technique by focusing on being more light and precise with your thumb.
Third, you say something about “have it (the pick) at a weird angle…”, that’s going to be a highly personal thing. Guitarists hold the pick differently, everyone uses different picks, and nobody’s hands are the same, so you’re going to have to learn by experimenting how much you do or don’t need to do this. The amount of pick tilt I personally add for this technique is very small.
Next, you show that you believe the technique might be easier playing notes closer to the nut: imo not enough to care about. No overthinking!
Next, regarding where the right hand hits. Every note on every string is going to have slightly different sweet spots, every note has multiple sweet spots, and there are some great sounds you can get by picking over the neck pickup. If you haven’t yet watched the video by Jacky Vincent, go watch it. It will show you the no-bullshit truth about this.
Next, you show some hand movement that people are recommending that isn’t helping you- wtf is that shit? That isn’t going to help you. That’s going to make everything a giant headache in in exchange for no benefit. It won’t help, it’ll give you ugly string noise, you can’t fit that into an actual musical performance, it’s just nonsense. Don’t do that.
A final note- how hard you hit the string is something not worth overthinking. I like to be fairly gentle for best results, but some guitarists get awesome sounds by striking the string. Try it both ways, but be relaxed.