The Grappling and Shoving rules state they are done as part of an Attack action. So RAW the answer is no.
If your DM decides to allow this there is another RAW snag to consider though, when can you make the PAM bonus action attack? Because the PAM bonus action attack requires all your Attack action attacks to be made with the pole arm it cannot be used until your Attack action is fully resolved. This is a common question with the Shield Master feat, so much so it has been addressed in Sage Advice.
All that said there is still the Crusher feat. Because the PAM bonus action attack deals Bludgeoning damage it works with the Crusher feat. All of this can be really nasty when paired with Sentinel.
After making my two attacks, can I use ny Polearm bonus attack to knock them prone or shove them?
The PAM Bonus Attack has to be made with the weapon you are using. So unless the weapon has some trait that would allow it then the answer is no.
Plus shove or knocking prone requires the Attack action, which the bonus action is not.
EZD6 by DM Scotty
https://www.drivethrurpg.com/en/product/397599/EZD6-Core-Rulebook?
The Grappling and Shoving rules state they are done as part of an Attack action. So RAW the answer is no.
If your DM decides to allow this there is another RAW snag to consider though, when can you make the PAM bonus action attack? Because the PAM bonus action attack requires all your Attack action attacks to be made with the pole arm it cannot be used until your Attack action is fully resolved. This is a common question with the Shield Master feat, so much so it has been addressed in Sage Advice.
All that said there is still the Crusher feat. Because the PAM bonus action attack deals Bludgeoning damage it works with the Crusher feat. All of this can be really nasty when paired with Sentinel.