Dolby Vision can  play HDR10, backward compatible  I think,

Anyway HDR10+ with Dynamic Metadata is already close to Dolby Vision and it's free, so I think it will be easily adopted.  Dynamic Metadata is the key feature that will make the previous HDR10 now consistent with quality throughout, no more hit or miss quality in future.

Any entry level TV has just the basic HDR support.

Which means it can decode HDR signal but the panel is unable to "show" the high dynamic range due to the inability to hit peak brightness as well as black levels needed for HDR image to really give the wow factor.

Esp when most entry level TV is basically full with 8 bit panel, hence it doesnt even have the wide range of color that can be displayed.

Just don't expect too much. Decent HDR panels are going around 5k+ now while flagships are going to 5 digit range.

Anyways for entry level you're better looking for TV you be better looking for a panel with the best Picture Quality you find acceptable within your budget range.\

I cant vouch for any brands, as different ppl eye have different preference (whether it is VA panel, or IPS panel)

Some ppl vouch by Sony, some Samsung, some Panasonic, and blah blah blah

The best way to do testing is to go Harvey (you dont need to buy from them)

Bring a USB stick or something with a video that you watch the most, ask them to loan you their remote, turn down their setting to regular movie setting, and eyeball all the TV within your budget range.

Picture Quality is very human dependent. What looks nice to you might not look nice to another.

That connector at the back is some sort of service connector not for audio.

Get an Optical to Analog 3.5mm output connector Converter.

But be careful, not sure if they downmix the full channels to stereo or they just output the L/R channels only, which means no center channel (voice) if original source is 5.1.
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Come to think of it you can always select the PCM option at the Tv to downmix first for you before output to the converter.

I read if you go into the service menu by using the convential remote (combo keypress) you can enable 2 extra profile mode for calibration and saving the settings, Cal1 and Cal2.

Please don't expect to get 10 bits panel on a Samsung low end UHD TV. The 55MU6100 is a PLS 8 bit panel with static contrast of 1000:1. The 55MU7000 is a 10 bits panel.