Move the module around, leave it for an hour or two.
I moved mine around, placing closer to each of my 3 cameras until I found the best location. It seemed to not be where I thought it would be, spaced equally away from all three. That wasn’t the case.
I ended up close to one of the cameras and far from the other 2 and they all showed 3 bars (full strength) after a day of sitting. I initially it was stronger to the cameras farther away, but it levelled out and now works perfectly between the 3 cameras.