Happy to know you have narrowed it down (just a little I guess...

. By the way, in re-reading an old thread on the R-N803, I noticed that it may have an a nice undocumented feature (not mentioned in the Owner's manual), that is, "
bass management". I don't know if it is only available after you run YPAO but it doesn't matter as long as the setting would remain intact once set, regardless of whether you engage YPAO or not. May be
@KEW can provide more details on this. For now, my understanding is that to access the bass management menu you have to use the Music Cast App.
If you use a subwoofer and don't want to use YPAO, then this is arguably a must have feature (again, assuming it would let you use the feature even after turning YPAO off). Follow the link below for more details posted by an user:
Yamaha R-N803 stereo network receiver with YPAO bass mgt! | Audioholics Home Theater Forums There is also a long thread on AVS with those screenshots.
Another thing, the amp sections and power supplies of the two appear to be very similar if not the same, based on available photos of the inside posted on forums, and comparing the specs of the two.
Also, if you compare the bench test results of Audioholics on the A-S801 integrated amp, and those of the R-N803 measured by ASR, they are in fact very similar:
A-S801, measured by Gene... 185 W into 4 Ohms, at 0.1%
R-N803, by Amir......................175 W into 4 Ohms, at 0.0061%
Yamaha A-S801 Integrated Amplifier Measurements and Analysis | Audioholics
Yamaha R-N803 Smart Receiver Review | Audio Science Review (ASR) Forum
So, I think it is reasonable to expect roughly the same 185 W into 4 Ohms at .1% THD+N, that's more than enough for the Elac DBR62.
One last point, if and when you do another listening test, make sure you reset the unit to factory default setting first. Your previous experience might have been affected by a messed up setting such as the impedance selector being set to 4 Ohms etc.