Re soundbar that really depends on your setup.
You should just output to TV, and then the TV uses ARC to talk to the soundbar, or the Apple TV goes into the soundbar input and the TV from there.
No need to choose the soundbar.
Now, if you happen to have an old soundbar without HDMI then you still need to pipe the sound from the TV to the soundbar. Older ATV have optical, which might be an option on some soundbars.
My brother in law because he’s a Luddite.