I’d recommend SVS speakers and sub…
https://www.svsound.com/products/prime-tower-surround-system
https://www.svsound.com/products/sb-1000-pro-subwoofer
Much better speakers than the ones you’re looking at, and all of them are available from their Outlet that reduces the total cost to $2245. IME the center speaker and sub are the two most critical for really good home theater, and these are a huge step up over the Klipsch. For the receiver, which is a great choice BTW, I’d highly recommend buying it through accessoriesforless.com as you’ll save a bundle — $700 vs $1150.
This brings you to $2950, and you can just add Atmos speakers later when budget allows if desired. To save more $$$ and/or be able to add Atmos speakers immediately, with your size room and a sub you could easily get away with stand-mounted front L/R speakers and save $600 over using towers. One of these two options is what I’d do if I had your budget, and frankly I think you’ll be blown away by the sound. Oh, and SVS offers a 45-day, totally risk-free trial (including shipping both ways) so if I’m a liar and you’re not absolutely thrilled for some reason just return them, and they also offer excellent customer service/advice if ever needed. Hope this helps, and best of luck. And congrats on finally realizing your HT dream!!!