Regarding the preout voltage ratings, instead of guessing, let's refer to the AH's wealth of lab measurement data. I thought I posted at least one the links below for the OP but may be he missed so here it is again:
https://www.audioholics.com/av-receiver-reviews/denon-avr-x5200w/measurements
and below is direct quote (also posted for OP before IIRC):
"The AVR-X5200W has plenty of grunt via the preamp outputs to use in conjunction with virtually any separate amplifier should you desire more power. I measured unclipped output of 4.5Vrms from every channel. We like to see at least 2Vrms and the Denon met this with over 6db of margin to spare."
From what I can remember, every Denon and Marantz AVR Gene measured before, showed unclipped preout voltages of >2Vrms. If I remember right, with few exceptions, Yamaha's also exceeded 2V rms in AH's lab measurements, though Yamaha typically specify 1V in their manuals, vs D&M's 1.2V.
The thing is, for comparison (between AVRs) purposes, you cannot just go by the data sheet numbers because when they tell you 1 or 1.2V, we don't know under what conditions. They could mean the voltage required to drive their internal amps to rated output, but then I don't want to guess.