It's extremely good that you are asking about picking technique! There are way too many shredder type quys with no right hand development, which is fine until you turn the distortion pedal off or pickup an acoustic.
There is no absolute one way of hand placement and picking. Most often the biggest concern is to not doing something limiting or harmful (carpel tunnel or tendonitis).
A ‘Death Grip’ however is rarely appropriate. This suggests tension and it’s difficult to play relaxed and/or controlled in a ridged state. Also, without that relaxed grip, you’ll wear yourself out for no reason. Hard music doesn’t have to be played hard to sound hard.
For single note work:
The pick grip is preference based. I hold them fairly traditionally, between the thumb & index finger.
Alternate picking practice is essential.
Flipping the wrist, I’ve found I have the most control with a rigid wrist, if you start playing very fast phrases, you’ll see the benefit of a rigid wrist, but again not all will agree with me.
Picking style, I use my three remaining fingers to act like a guide over the strings being anchored on the pick guard or body. They keep the height of the pick off the strings consistent and float up and down the guard / body as the rigid wrist moves up/down, sort of like a record needle.
Right hand placement is again preference based. I use two, for Les Pauls and acoustics, I rest on the bridge and pick from behind it. On strat styles and related, I rest near or in front of the bridge and pick from in front of it.
My 2 1/2 cents (you got a free upgrade)