Phantom 4 Advanced not used for 3 years now have lots of problems

Haven’t used my P4 Adv for almost 3 years. Charged all 3 drone batteries in the charger and all seemed to charge OK. Only 1 now holds charge and switches on.
Charged controller and it switched on ok but then the message “Unfortunately, DJI4 App has stopped.” comes up.
Can’t link to the drone.
Updated firmware on drone. Tried to update firmware on controller - no success.
What do I do and in what order???
Really would appreciate help with this.