Lock mode and Legacy mode are two different ways of interacting with controls. Lock mode was introduced when MSFS came out on Xbox. I think it may be default or the only option on Xbox. Legacy mode is the way people used to interact with the controls and requires a mouse.
I am on PC but still prefer Lock mode.
To activate the cursor I think you click on the inner knob
I only started using this on Xbox last night,bit fiddly,think I Left clicked hold inner wheel then add right click then pull the cursor/knob to the edges of the screen up/down/ left/ right to move map etc,but it is awkward.Also your 2nd question,mine always air spawns in autopilot ,just steep right bank to disconnect it.