writing programs for servicing 7 servos by means of a potentiometer and two motors controlled by means of analog sticks (one stick controls the front-rear vehicle, the other turns, ie the motors work alternately). of course all based on arduino mega2560 and HC-12 modules. How many would you for this?
You'll need to do a much better job of describing the project. What, exactly, do the 7 servos do? What, exactly, is the relationship between the position of one potentiometer and the position of each of the servos?
Reading the potentiometer is trivial. Controlling the position of properly powered servos is trivial. Controlling the speed and direction of motors connected to a motor control shield, with proper power, is trivial.
Sending and receiving serial data is pretty simple.
The hard part is determining what to send, and when to send it. If you expect someone to write a program for you, to send the data, you still need to do that part.