A:AnswerNo you will not need internet but you should have internet with the first time set up because any updates that they fixed any bugs or problems will come in that update.
A:AnswerEither way is fine if you have Dolby Atmos pass through your TV I've had and still do have my Blu-ray and my Fire Stick on a splitter going to my TV I thought I'd try that set up. My old TCL didn't have that Dolby Atmos so then I would have to directly connect it to the sound bar. But as long as you're splitter is 4K you should be okay I had a splitter one time switch go bad and it wasn't only putting out maybe 720p so I just hooked it to the TV when I got an oled that can handle the pass through The only problem is is when you have a directed a sound bar I think you'll get the audio right away when you play the movie sometime there's a short delay going through the TV when you play.
A:AnswerIf you're concern is whether you're not getting 4K or not as long as your TV is saying UHD you're good to go my TV is a Vizio OLED and usually it just says HDR or Dolby vision unless you're going into info on the TV you'll see the more exact specs of what's playing. But mine does not say 4K in any notification.
A:AnswerBefore I set up my fine speaker sound system in the bedroom, I was using a sound bar and was very happy using the television out into the sound bar. I was using an optical cable but RCA or HDMI, quality cable will be fine.
A:AnswerThis unit supports many varieties of surround sound. Also supports Dolby Atmos. Just depends on the capabilities of yout tv sound system or Audio Video Reciever.
A:AnswerOptical / TOSlink is a very old and it used to be a good method for sending digital sound. That isn't the case anymore. Toshiba invented it in 1983.
TOSlink does not have the bandwidth to carry uncompressed versions of Dolby TrueHD, DTS-HD Master Audio, or more than two channels of uncompressed PCM. And it and isn't compatible with Dolby Atmos.
Get a good 8k HDMI 2.1 cable and connect your TV to your A/V receiver through the eARC HDMI port on your TV. Your sound will improve quite a bit.
As far as picture quality and sound, in general, what you get with more expensive 4k players is this:
Better DACs, better processors for upscaling DVD and Blu-ray to 4k. You get more discreet audio channels if you want to connect component sound directly to the player and you get codec for DolbyVision color (which is better than HDR 10 and HDR 10+). DolbyVision is only going to matter to people with a TV capable of displaying DolbyVision (Samsung TV's ARE NOT COMPATIBLE WITH DOLBYVISION).
I hope that helps you.