Omni polar sounds like bipolar. That’s the old way of doing theater. I used that for many years and it was a wall of sound and reflection of sounds everywhere. That worked for the older formats but now they are “placing” objects in the room with Atmos/DSU & DTSX/NeuralX, so monopole speakers are back and surrounds are lowered to ear height with the addition of ceiling speakers.
I wouldn’t build a system without a decent sub (unless trapped in an apartment where I couldn’t use it).
Like was mentioned, only you can decide what sounds best.