Question about Denon AVC-X3800H

Yes, it is possible to operate the two front speakers with bi-amp in a 5.1 setup with a zone 2 (stereo 2.0). The AV receiver supports bi-amp connections for the front speakers in 5.1 mode together with Zone 2 by making the corresponding "Amp Assign" settings, e.g. "5.1ch (bi-amp) + ZONE2". The additional amplifier channels are used for the bi-amp connection of the front speakers, while zone 2 outputs stereo 2.0 separately.