Getting 4K to work on Apple TV 4K with Yamaha RX-V573 and LG TV

It's good of you to share this info. You've chosen the least common denominator as far as video features go to maintain compatibilty with your AVR...

Most folks won't see much difference in frame rate (24 vs 30 vs 60Hz), but you're sort of missing out on the color-related HDR / Dolby Vision capabilities of your ATV4K and LG OLED TV. If cable management isn't a show stopper, I would run an HDMI v2.1 cable directly to the TV from the ATV4K (and reset/reconfig all the video settings on both devices). The Yamaha should still sound good with what gets back to it via ARC / HDMI 1.4.

TLDR: I suggest leaving Match Content OFF. If you’re seeing problems, double-check your TV’s settings to accept HDR10/Dolby Vision and if you still see problems, try turning on Range then Frame Rate. Honestly, if you’ve got a high-end TV that’s correctly setup for Dolby Vision, you probably won’t see much difference either way.

There are differing opinions on the Match Content feature. By default, with Match Content = Off, the ATV4K is essentially converting all video content to the selected format - in your case 4K Dolby Vision. This puts the ATV4K’s substantial chip to good use (involves some serious math), and by most accounts the ATV4K does a good job of it. If you turn Match Content on for dynamic range and frame rate, the ATV4K passes the video along as it was encoded, and your TV will switch modes to render the video at the encoded frame rate and dynamic range. I believe the scaling from old SD and HD resolutions to UHD/4K also passes to the TV with Match Content turned on.

Some complain that their TV doesn’t look good with the ATV4K doing the work or they like to see the “HDR” or “Dolby Vision” mode change banners at the start of each program encoded as such (instead of just once when they switch on the ATV4K :-). Others complain of a “soap opera effect” when the ATV4K converts 24fps HD content to 60fps UHD/4K while also figuring how to artificially increase the dynamic color range to HDR10 or Dolby Vision. A downside of turning on Match Content is watching your TV’s screen momentarily go blank as it switches modes to adjust to every content change.

I used to have match content turned on for both Range and Frame Rate because I like to mess with settings, but when I reset my video settings on the TV (enabling the best it can do on the HDMI port connected to the ATV4K), and then reset the ATV4K to settle on 4K HDR10 for all content (my cheaper 2020 LG doesn’t do Dolby Vision :-), I realized that the ATV4K does a darn good job of video processing and that my TV was too slow and annoying anyway when switching modes all the time.