Where are you flying?, do you have a clear LOS, or do you have obstacles in front, say trees, buildings? Out in a field, with no trees, you should get easy 1 mile and possible 2. 10500 feet is my best on a MPP. It gave up the ghost at that distance and disconnected and started a RTH. Quickly reconnected however. I normally never fly out that far, as my main goal is photography, and at that distance, you have very little time to do anything but turn around and come back. I only use the stock controller, no antennae add ons or boosters, or changed out antenna. for some of the after market stuff.
I am in Arkansas, and with the MPP, I never have signal issues with distances at 2000 feet. Rarely do I have a 100% LOS, having to fly over near by trees.
Couple of thoughts, what is your height? You can fly up to 400 feet now and the higher the better signal strength at least this is what I have found. Lower to the ground at distance will kill of your signal very fast.
What is your signal 5.8 or 2.4, the MPP for me is better at distance at 2.4. You can take it Auto and peg it to 5.8 or 2.4 only, just to see. In the wild outside of the city, I prefer 2.4, but around the city, I find that 5.8 is better.
Of course you are I am sure pointing the controller towards the direction of the drone and keeping the antenna upwards?
Lastly, what are your signal strength bars showing, when get the message? Best for signal and HD (your video coming back) is 5 bars. When you see the signal warning, what are the bars? You can see this on both your DJIGO4 screen at the top and on the controller screen again at the top. I ask this because I have seen this same message, but I still have 5 bars of signal, which never drop. I am more focused on the signal strength bars.
If you fly near another MPP, MP, M2 Pro, or even a
Phantom 4 Vr 2.0, you can get signal strength warnings. A lot of people say they often fly next to another pilot, however every time I am within 10 to 20 feet of a friend with a active controller, I tend to get the same warning. And this one I do pay attention to as a conflict from another controller can be IMO a show stopped, and all you have to do is move about 5 to 8 feet away.
Paul C
2 Pro The Holy Monastery of Timios Prodromos in Serres: History, Beauty and Spirituality