[Why is my A300 going to toga? (XBOX MSFS 2020)]

Are you disengaging the AP on approach or the AT? You push the throttles full forward on takeoff and then engage the AT, when landing if the AT disengages the engines will spool up to where the throttles are set. To avoid this you can either take manual control of the AT on the EFIS or pull back on the throttles first prior to disengaing the AT and then adjust from there.

This may or may not be your issue, but this is something that has caused unanticipated engine thrust to me in the past until I figured it out. This also applies to numerous planes.

[ATC sound]

I have it set it up as shown, and have tried multiple other configurations, including all volume knobs turned up, and I still am getting no sound from the stock ATC. I've been troubleshooting this for 2 days now since it seems like it works for some other people, but maybe not for my platform? I am on Xbox Series X and using MSFS2020.