btw, your AVR probably has a 2 channel mode. I often find changing to 2 channel sounds better.
That will reassign the dedicated center sounds to both sides equally so that center content’s imaging is still center (but phantom center created by L/R), and still coming from the front.
And no ’other sounds’ from the surround/rear speakers which may be affecting what you hear (your cupped hands are blocking side/rear/reflected sounds).
Sometimes, in a noisy space i.e. restaurant, theater lobby, ... I hear sounds from a distance better than those right in front of me, seems like the other sounds are a precedent, fill my ears so to say..