Making a boat autonomous using trolling motor and a stepper motor

Hi everyone

I am building a self driving boat which will use a trolling motor for propulsion and a stepper motor as a steering but then I find a problem with how a trolling motor is going to be controlled by a pixhawk and also determining a speed controller suitable for trolling motor. For stepper motor

Generally, a trolling motor is just a dc motor that can be controlled by a rc brushed motor controller but it depends on exactly what one you have. Any particular reason to use a stepper motor and not just a large servo or liner actuator?

For stepper motor I was thinking of using an Arduino to connect it and follow the commands from a pixhawk. By the way I’m gonna be using 12V to supply all the electronics.

It would be grateful to have your tips and suggestions.

For my application I need a good positioning, I’m actual building an autonomous surfboard therefore a stepper motor has a high torque at low speed which I think is good when it comes to positioning of the users.