Could I make 5.1.2 work in-ceiling (except sub), meaning far from ideal but still enjoyable/believable for a family room? Would this setup be best or could it be improved?:

Front LCR: HTR 8000 (or HTR 7000)
Rear LR: HTR 7000
Atmos LR: 650s directly down (or HTR 7000 angled?)
Floor-Standing Sub: suggestions?

Setup: MLP is 11' from TV wall, sitting on couch so ~40" from ground, ceiling height 9' 2", total room size 22'L x 12'W.

I've heard that 7.1 is a waste because movies don't use it and rear and side surrounds produce same effects so just added noise, only good for multi-row seating. But have also been told 7.1 with surrounds placed in U-shape creates more enveloping sound stage.

I've heard Atmos MUST have speakers on different levels (ear+ceiling), all in-ceiling is a scam. But have also been told that's not true, would still sound better than 7.1 or 5.1.

Appreciate any help and feedback based on direct experience.