Atmos is of great benefit with 4 ceiling speakers. It's sort of worthless in a x.1.2 configuration.
Also, I don't see any benefit of 7.1 over 5.1 in your situation.
So, 5.1.4 would be where I'd be going if I were you.
The only other place where 7.1.4 may be of use over your 5.1.4 is for rear rows as your main listening position can be just as good with 5.1.4 as 7.1.4. But if you have several rows behind you, adding the rear surrounds may be of some use for guests.
Video: JVC RS4500 135" screen in pure black room no light, htpc nvidia 1080ti.
Audio: Anthem mrx720 running 7.1.4, McIntosh MC-303, MC-152, B&W 802d3 LR, B&W HTM1D3 center, B&W 805d3 surround, B&W 702S2 rear, B&W 706s2 x 4 shelf mounted for atmos, 2 sub arrays both infinite baffle: 4x15 fi audio running on behringer ep4000 + 4x12 fi audio running on 2nd ep4000.