An ideal (minimal) 2.1 setup

where's the center channel speaker?

If the program content has center channel info, and you have no center channel, then don't you have to downmix to forced 2 channel mode?

If you just don't hook a center channel up, the center channel signal is still NOT in the front L and front R.

A 77" image, movies, only 2 channel?

At least consider having HT Bypass feature for future options

We just thrashed out how to have an excellent ’FRONT’ 2 channel music system, like what you are planning,

and have an AVR for movies. AVR uses that high quality 2 channel system for the front and the AVR drives the ’other’ movie sound channels, i.e. 5.1 .. Center, rear surround L & rear surround R.

https://forum.audiogon.com/discussions/avr-internal-2-channel-audio-mode-or-ht-bypass-external-equip...

Bass: Subs: you will want ALL the BASS to be part of the FRONT 2 channel system, thus ALWAYS there via Large Mains, or a PAIR of subs front firing, no ports, adjacent to the smaller mains. Directivity, Imaging comes from the fundamentals and all of those fundamental's overtones, i.e. 40/80/160/320 ....