You already have a 5.1 setup? Assuming you "only" need an Atmos processor and a few speakers you could get by cheaper.Yep, it’s going to take about $4,000 worth of hoop-jumping before I get to listen to Atmos in my room. I’ll do it, but it’s far from the top of my giterdun list.
When I built my Atmos system, I already had a good base 5.0 and an inexpensive sub. I also had 4 identical speakers that used to be my "pc" setup so I just incorporated those for the height speakers. Not expensive at the time I bought them, just Polk Monitor 30's. I later filled out the surround backs with a pair of Klipsch "refurbs" I bought off the Amazon, as my base 5.0 speakers are no longer sold.
I know others can and do buy more expensive equipment, but for my retirement income level I'm happy with what I have.