I'm not understanding how/why the pick would keep spinning on you guys...?...it must be how you are holding it.
I guess if you just pinch it between your forefinger and thumb, it's going to spin...but I've never held a pick that way going back to my fist lessons as a kid.
I hold it between those fingers, but also with my middle-finger...so it's kinda cradled between my forefinger and middle finger, with the thumb pushing down in-between them.
It never spins, and I find that it provides much better control for a variety of picking dynamics. I also don't "flat pick" the strings, but with the hold I use, I'm actually picking the string with the pick at a slight angle, so the edge at the tip of the pick is what comes into initial contact, not the flat part of the tip.
If you just hold between forefinger and thumb, with the other three fingers kinda fanned out...it's not going to give you much control, and it's a lighter kind of pick action with more pick flap.
The way I hold it...it also allows me to keep the pick between my middle finger and thumb, and then I can extend my forefinger and just pick the finger, which is a different tone altogether.