Receiver’s Preamp Out: make sure it has Front L and Front R preamp outs for future options.
NO WAY are you going to use the TV’s speakers.
7.2? are you going to buy/install all those speakers and then use the TV speakers?
I recommend a simpler and effective 5.1 system (7.2 AVRs have 5.1 modes), with a real center speaker, horizontal, located just below the TV so dialog is from the TV.
Mine, no rear ports
https://www.klipsch.com/products/r-34c-center-channel-speaker
rear surround, just enough to add something, not aware of them until you turn them off, or, obviously rear content like helicopter in Black Halk Down, that sort of thing.
I use a small pair on their backs, using the space between the rear wall and back of sofa kind of like a horn. I stuffed their rear ports
Sub, not too big, but add some dinosaur stomp like Jurassic Park.
Now, the most important: Front. Efficency close to center channel’s efficency to easily balance their respective volumes.
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ARC is Audio Return Channel, so equipment works together tricky to understand, but you want it.
Some devices use two HDMI cables, one for viseo, 1 for audio. I got mine working, with help from Sony. Your maker will help you get it all working.
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Always Video? or sometimes 2 channel music? More to say about that if dual use.