I'd personally regroup and think this through. You're not going to get any real benefit out of Atmos without having surround speakers, it's just not how it works.
So I would put more thought into how to incorporate a 5.1.2 setup into your room. A diagram or pics of your room would be beneficial.
Once you have that figured out, focus on the LCR, sub, and AVR. The surround and Atmos speakers can be less quality, and always upgraded down the line (the same can be said for the AVR as well).
Vizio P65-C1 (2016)
Onkyo Tx-NR656 (5.1.2 setup)
JBL Studio S-Center, JBL Studio S26ii (FL/FR), JBL N24 (LS/RS), JBL N24 (Overhead Atmos), JBL Studio SUB250
Nvidia Shield TV 2019 Pro / Fire Stick 4K