volley is the easiest stroke... there is, literally, NOTHING to it.
conti grip, slightly eastern is fine.
start with relaxed grip, make sure racket head is above the hand... grip pressure is 3 out of 10.
now, use a ball machine, use this set up, just catch the ball.... don't worry about unit turn, don't worry about punch, don't worry about nothing... just catch it, like you were catch it with the palm of your hand.
ok, so with the 3 out of 10 grip pressure, the ball won't go anywhere, it will probably just die on your side of the net.
don't worry, now try this - as the ball comes in, you still try to catch it, but now you also squeeze the handle, increase grip pressure to 8 for a deep volley, or to a 4 for a drop volley.
I once used this analogy and people went speechless.. when you squeeze the handle to grip pressure of 8, the racket works like an erection, it has plenty of power to hit a forcefully volley this way, without you swinging forward.