You need a 2nd SDR.
How to Install and Configure Piaware 5.0 SD card image - Quickstart Guide
Try a gain of 25, maybe go down to 20, you can even try 15.
(It’s normal to lose some range, that can’t be avoided if you want good close in coverage)
For Beginners - How to Set / Change Gain
I’m not sure if FA displays traffic taxiing on the ground on the global map.
There are other tracking sites which do:
- FR24 limits it to after and before a scheduled flight i believe so that will likely not work for you
- adsbexchange displays all aircraft on ground all the time if they have their transponder on and are being received so that would work
- Don’t know how planefinder and airnav handle it