When setting my sensors up I always used hcitool lescan to test the range. Since I have 2 of my Miflora sensors in my green house i had to do some testing before i found a good position for both sensors and receiving Pi3. So if lescan can find your sensor address then you’re good.
I have about 30 m to my greenhouse but there are only windows in the way. It’s also a good idea to know where the antenna for Bluetooth is on your Pi3.
Also, since you have added a median to your sensor it will take 3 readings before a value is displayed in HA (FYI).
Another tip is to make sure the sensor is updated. You can do that with the Xiaomi plant app, but before any data can be read by HA it must be unpaired from the app.
I hope these tips help you.