Twin T200 Surface Water Craft - Arduino Speed and Direction Control

I have two T200 thrusters mounted on a surface water craft using BR ESCs.
The ultimate project is to send this craft offshore up to 1km through waves with remote control of direction and speed. (not GPS control at this time).
Step 1: I have basic Sketch to control each ESC with two separate linear pots wired to each ESC on the craft. Control port and starboard motors seperately (forward and reverse speeds). Testing in my swimming pool with long wires.
Step 2 - Wired Speed and Direction with Joystick
Looking for Sketch that combines speed and direction through either two slider pots or joystick (2 pots with return to center spring and switch button). Someone has mentioned “skid” steering and “differential” steering - I am confused.
Ideally I would like one pot of joystick (eg Up/down) to be speed - center stopped. And left/right pot of joystick to be direction - center straight.
(Dump question: Most joysticks have return to center spring - craft stopped position.
How do you maintain last speed and direction from last position of joystick. The mission will be up to an hour long so only want to change speed and direction occasionally when off course.
I am thinking this is where switch button on joystick may be pushed to alter the speed and direction - is there a better idea?)
Step 3- Remote Seed HC-12 Transceiver Operation
I want to connect one Seed HC-12 Transceiver module to the Arduino Uno on the water craft with a remote antenna. Connect the joystick to a second Arduino Uno and second HC-12 Transceiver module in a hand held remote controller and send speed and direction signals to the water craft.

I am a novice so appreciate any IDE Sketchs that may assist and any suggestions for Step 2 and Step 3.
Thanks in advance
Richard

Hello Richard,

You should get an RV antenna that extend WiFi reach and control it with qgc. This way you also have video, gps joystick control etc.

I spoke with them a while back and they claimed space x uses them on their recovery barge. You just basically connect to it with your laptop like a normal WiFi network.

Also, I sell a joystick with trim so you could dial in the trim forward and use the joystick to correct the course heading.

Another reason to use the Bluerobotics control system is the support that comes with it and the tons of examples in this forum.

Cheers,
E