Yes, you can bypass its internal configuration assignment in this manner.
For hifi purposes, you should eventually move away from the AVR and get a purpose designed preamp processor, i.e., it will have no internal amp sections. You connect the pre-outputs of such a processor into external amps or a beefy multichannel power amp.
Even a flagship AVR is only good for hometheater, movies. For music, you will need a dedicated processor and separate amps and correctly gainstage everything. It is never a good idea to shove all those power amp sections into the same chassis.
For example, this marantz would be a good fit.
https://www.accessories4less.com/make-a-store/item/marav30blk-a/marantz-new-av-30-11.4-channel-balanced-av-preamplifier-powered-by-heos/1.html
Or here’s a refurbished unit for a bit cheaper.
https://www.accessories4less.com/make-a-store/item/marav30blk-rb/marantz-av-30-11.4-channel-balanced-av-preamplifier-powered-by-heos/1.html
This older Rotel, for example would be a good barebones processor as well, with a focus on sound quality for around a 1000 bucks.
https://www.ebay.com/itm/336398263929
@travelinjack wrote
On the X4800H, since the main front left/right speaker output and pre-outs are all active, does this mean it’s possible to bi-amp using these?
If I connect the main front left/right to the high frequency on the speakers and then the pre-outs to a pair of Fosi V3 mono blocks which would feed the low frequency on the speakers?