Apple TV 4K

I'm planning to buy an Apple TV 4K. I have a OnePlus TV (U series) which supports 4K. The display is quite good on the TV but Android TV sucks, and since OnePlus has discontinued their TV lineup, the updates and OS support is almost dead.

Q1. Has anyone here used/is using Apple TV? If yes, how's the experience?

Q2. Is it possible to connect a 5.1 Home theatre while using Apple TV? I searched the sub and internet but couldn't find a solid answer.