What pi and dongle are you using? I had a lot of trouble getting my zero W to work properly and found the answer was to use a USB extension cable to get the pi and dongle 50-80cm apart. It wasn’t behaving like yours though.
In addition to SweetPea11’s suggestion, I have found the gain optimisation script useful. I did change the time period between gain settings to 5 sec though as I found 62 secs was too long. The planes in my range moved too much in 17 mins (which is how long it takes each cycle) for me to get any really useful data. The script will leave the gain set at whatever the last test setting was (i.e. if it runs through 5 times, it’ll be set on 20.7)