For the AI traffic the best set of working s/w i've found is the following combo (all available via flightsim.to):
"Easy airlines+aircraft matching with default live traffic" by Headwind - that provides pretty good model matching for live flights
Follow each step in his setup directions...it works...and make sure you install the optional static AI at the bottom of his instructions - that keeps aircraft where they should be at the airports.
If you want even more live AI traffic try Enhanced Live Traffic by MrPropper - it uses real time FlightRadar24 data to populate the world and pulls in smaller aircraft than MSFS will (like light civil aircraft doing pattern work at airports) - you HAVE to work with the model matching some but it's gotten a lot better and will fully use the models installed in the steps previously mentioned.
Using those tools I have a live world where you can see jets at the gates well before the push back...you have a busy flight environment and PF3 interacts with these aircraft just like yours. I just landed at Los Angeles Intl (KLAX) and the ground controller was very busy with jets that just landed and the 'controller' does a decent job at deconflicting taxi routes...without hard-coded dedicated taxi routing it's hard to deconflict a near constant stream of aircraft coming and going at major airports and will lead to inevitable head on games of chicken (better that in the SIM than in real live!)
Enjoy and fly safe!
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Flying the friendly skies of MSFS
XBox handle: mikejenlyons
Discord: m_j_lyons
A Pilot's Life 2: Michael Lyons
-- mike