Before I had Atmos my old AVR was rendered obsolete because it woulnt properly fold down Atmos titles to 7.1. It would lurch and tick and pop unless I changed the output of the BD-103 to PCM from bitstream.
It was a bummer. It was a pricey AVR and was otherwise Ok. My signal chain no longer supported the new audio codecs.
If I was to buy a TV these days I would be sure it had eArc is all. I beleive that supports immersive over HDMI. But worth verifying on your model.
Something i was going to be incorporating as a necessary feature; eARC. The Sony A9G series does not have HDMI 2.1 but it does support eARC on one of the HDMI inputs. I believe you have to get their Ultimate chip and not the Extreme chip to have this feature on Sony OLED.
The reviews say that Sony still wasn't 100% clear whether their 2020 lineup would support HDMI 2.1. They are falling way behind if they don't. The reviews also say that most of the features with HDMI 2.1 are more important for gamers with the exception of HDR. If HDR isn't a must thing (and frankly it won't be for many people), then as long as you have eARC, the rest is moot.
Our system will not be a gamer system and even if it was, none of us play so seriously we need those features.
I had looked at an AVR earlier this year but there was no point in buying just yet. Was still sorting out all that was going to change around in the home systems. There's more than just HT electronics that needed replacing this year. I just got a new monitor yesterday!