Slightly edited.. Your post. I don't yet see the advantage of this over say a Denon 4800 or a 6800H, as someone else remarked... I am also a fan/proponent/elated user of
@OCA scripts and don't plan on leaving the Denon/Marantz ecosystem for the foreseeable future .
As for the reliability of Denon/Marantz because of the supposed "Heat build-up", I have not experienced such, and in eco-mode my old, purchased refurbished in 2017, AVR-X3400H, doesn't offer the possibility of shutting down the built-in amplifers when in Pre/Pro mode. Using it in eco-mode it playing as a preamp, consumes (measured) 65 watts, I have been using it in this mode for the past 8 years without, any "Heat Build-up" nor any other problems .. Cross my fingers.. next step could be either a 3800 or a 6800H, this last one often goes on sales for around $2500... It boasts 11 (!!) 140 watts amplifiers... I there is any sign of "Heat build-up" one can address this with a bit of non-invasive or irreversible DIY: Some silent fans on top or wherever appropriate would solve the issues, if indeed these are serious... on top of that the 6800H, offers 7 (!!) HDMI (2.1) inputs and 3 HDMI outputs, as well as 6 analog inputs
and 6 analog outputs and ... the possibility to enter your own (FIR??) filters...
Yes it is big and f-ugly but ... but It seems to provide a lot more ... aside from (likely inaudible for most) better SINAD and balanced outputs... Just saying ... After reading the latest posts of this thread, I am not convinced by this product.