Kitchen wall mount TV with flush speakers?

[AM-BM]

Hi. Need a bit of advice on the new kitchen system.
Currently running optical off the sky box to my lounge AV system.
I will need to switch sound to hdmi and run cat 6 network to the kitchen
So I can have the Tv linked to my AV receiver.
I'm guessing it will have picture and audio over the Neet Hdmi converter.
I then need to find a decent sound bar that will sit flush under or over the wall
Mounted tv as I we will walk past it and dont want it jutting out.
However it seems all the good soundbars are quite deep (built in subs).

I'm hoping the 2 cat 6 cables will carry picture and sound.

Also the sound bars usually require optical to connect so once the TV takes the HDMI
Signal I can plug the sound bar into the Tv with optical to get sound out if it?