I added a moveOnPath command to DroneShell which calls the DroneControlBase::moveOnPath method. So to demonstrate this I downloaded the Modular Neighborhood pack from Unreal marketplace, and set the player start position to the following location:

x=310.0 cm, y=11200.0 cm, z=235.0 cm

Then I arm the drone and takeoff, then I executed this command:

Moveonpath -path 0,-256,-4,126,-256,-4,126,0,-4,-5,0,-4 -velocity 10 -lookahead 10

You can go faster if you set this PX4 parameter:

param set SYS_MC_EST_GROUP 2
param set MPC_XY_VEL_MAX 20
param set MPC_XY_CRUISE 5
param set COM_OBL_ACT 1
param set COM_OBL_RC_ACT 5
param set NAV_RCL_ACT 0
param set NAV_DLL_ACT 0

Here's the result, see demo video: