I have a Bose Soundbar also with Chromecast and that one doesn't suck down 25W+ while on standby and can thankfully turn on the TV via HDMI CEC.
Sadly the whole OS experience is shitty on the TV. It's 2500€+ TV and the UI is sluggish, Tv takes at least 5-10 Seconds to turn on each time and still comes with the classic google ad like interface.
I bought a Chromecast remote that works via bluetooth to somewhat make the remote feel a bit faster, but it sadly just makes a tiny difference.
Nvidia Shield still feels like the only real option when you want a non sluggish Interface on your multi-thousand euro/dollar purchase.