I have seen many team pick up ball in load zone since the ball can’t roll out the zone, so is it legal to access it?
What do you mean by the “load zone”? Do you mean the “Pickup station” that is attached to the goal wall? If that is what you mean, then you cannot pick up the balls unless the ball touches the field first. If you have removed any other balls that might be obstructing it, your only other option would be to score another ball in that side, or ask the refferee to liberate the ball from it’s confinements.
Oh yeah, look at < SG> in the game manual for the rule: RapidRelay-1.1.pdf (vexrobotics.com)