So, bought a new setup.
Samsung 8D QLED TV
Nakamichi 7.1.4 soundbar (Bluetooth sub with rear speakers wired to sub)
AppleTV 4K box.

This to replace an older 5+ yrs Samsung 55” LED
Sony 5.1 wired surround system.
Roku 3

With the old system the DIRECTV box along with the Blu-ray/DVD player and Roku were all wired via hdmi into the surround receiver, with a single HDMI going up to the TV. No issues at all with picture clarity, sound, etc.

With the new system, have the DIRECTV wired into an HDMI port on the TV, and the HDMI (ARC) port on the TV connected to the HDMI ARC port on the soundbar. Then have the AppleTV box and Blu-ray/DVD connected to HDMI inputs on the soundbar. This is per the recommendations from Nakamichi.

While watching DIRECTV, everything seems great. Picture is great, and sound is great with the sub and rear speakers doing what they’re supposed to do. When watching things via the Apple TV, for example HBO max, Netflix, Amazon, Apple TV, the picture seems dark and the sound is hit or miss. Often get a static sound coming from the subwoofer like it’s not getting a good connection.

So, reconnected the Roku 3 to the last HDMI port on the sound bar and did a back-and-forth comparison between watching the same episode of Young Sheldon on HBO max on Roku and on the AppleTV box. The picture and sound via the Roku box through the sound bar was awesome. The picture and sound via the AppleTV box through the sound bar sucked.

Then, set up the AppleTV app on the new TV and put on Greyhound. Picture and sound again, when not using the Apple TV box, were awesome. When watching Greyhound (great movie, by the way) via the AppleTV box through the sound bar, the picture was dark and the sound wasn’t right (sounds like static or interference in the subwoofer connection).
Also, with the Apple TV box, the picture will sometimes get blurry, the sound gets out of sync, and sometimes it would just freeze, and a message would come up that they weren’t able to play the video at that time. As if we have a bandwidth issue with our Wi-Fi, which we do not.

So, it seems this AppleTV box is useless. It appears the new TV and the Roku 3 box can cover all the things I was expecting the AppleTV box to do. So, this Apple box is going to get returned to Amazon.