Stage four of the serving progressions; throw the ball to go over the net to your partner with no bounce, stepping forwards with the opposite leg to the hand that you roll with (using body weight) and releasing the ball slightly higher.
New hitters rarely miss because of their arm. They miss because of their feet. Build a reliable approach, then time it with your setter.
When your hitter gets stuffed, five teammates standing and watching is how you lose the point. Good attack coverage turns a blocked ball into a second swing.
Coaches spend hours correcting arms in serve receive when the real fault is almost always the feet. Fix the movement and the platform fixes itself.