Wrong forum. We focus on high end 2 channel sound and reluctantly tolerate HT systems in the same room. Some of the more affluent members here has seperate theatre rooms in their home. But you can probably find an HT forum where people focus on what you are doing.
ignore @carlsbad , he is just misinformed.
I use the exact type of system you are asking about in two setups, my main system and my man cave.
You will need:
1) A 4K TV with HDMI connections (with something called ARC or eARC).
2) A 5.1 (minimum) capable receiver (Denon/Yamaha/Marantz, etc).
3) A set of matched speakers and a subwoofer
4) An X-Box or Play station
Your soundbar is really for watching TV, not gaming. Of the stuff I listed what do you already have and what do you still need to get?
I got this,...
I've found that the center channel (which has input 100% of the time), is most important with surround sound. I have a 7-channel system upstairs using Martin Logan speakers, a Marantz pre-pro, an Aragon 7-channel amp and an 85" Sony.
Downstairs I have an 11-speaker, 2-sub system, using Klipsch speakers, an 11-channel Monoprice amp, a JBL Synthesis SDP-55 processor, an Optoma projector and 130" screen. I prefer this Klipsch-based room over the upstairs Martin Logan room. But both are good.
Thus, for the Price and for Surround Sound, I don't think Klipsch speakers can be beat. My 2-channel room utilizes Majestic 845PX SoundLab speakers and it is entirely another story.