[The M109 howitzer] could “shoot and scoot” still to avoid counter battery fire by moving to another predetermined location.
I'm no military expert, but I can do some elementary arithmetic. I don't see how the M109 could fire many times before it gets hammered.
, the M109's firing range is 21 to 30 km. The vehicle's maximum speed is 56 km/hr.
The PLA has many different kinds of drones (over 1500 different models). I pick one almost at random, the , with a payload of 10 kg and speed of 500 km/hr.
Let's say the M109's first target is at maximum range, 30 km. A Thunderbird launched from beyond that range, say from 31 km -- and therefore guaranteed not to be damaged by the gun -- can reach the howitzer's firing position in 3.7 minutes. At the SPG's maximum speed of 56 km/hr, the gun could scoot 3.5 km in those 3.7 minutes, which is not very far. The drone should find the moving gun quite easily; locating the gun would be even easier if the PLA sent several drones (why not, they're cheap).
Once a drone locates the gun and follows it, sending real-time position information to the PLA, how long do you think the M109 will last?