Only the Samsung has 4 upfiring speakers. The ST5000 only has 2, and they don't create very convincing height effects. I have had both — the ST5000 sounds significantly better for 95% of what you will watch or listen to. But it can't do Atmos like the Samsung.
At this point, I am excited about the Z9F again. If I could swap the ST5000's upfiring speakers for wireless rears and save a few hundred bucks, that sounds really good to me, and that's what the Z9F appears to do.
LG B7 65", PS4 Pro, Switch, Roku Premiere+, Samsung K8500, Sennheiser RS185
Denon X4400H, RSL CG23+CG3, Onkyo SKH-410, Emotiva BasX8 (5.1.4)