None of my avrs with zones have any delay adjustment for such that I've ever noticed (tho no Marantz units), but then they're not really meant to be used together otoh. I have a zone on one avr for deck speakers and standing where I can hear both the mains and those, maybe a very slight delay, but hard to tell due to the other speakers not being very close and one outside, one in the workshop nearby....this was just having both zones set to the same usb source in simple stereo mode (don't think all-ch stereo would change that).
How did you experience/test the delay in yours?
Interested how this works so tuning in, have played little with my zone capabilities....good luck in any case!