If you spend about 13 seconds searching Google about issues with 4K, you will see that 8K is a LONG ways off. 4K isn't figured out. Not even close. Yes, people can shoot it, edit it, encode it down to a streamable rate that looks great, but once it is decompressed and pulled out of a device at 18Gb/s, it suddenly is hitting some major cabling barriers that haven't been figured out except for the most standard setups. TV on top of a component with a single cable? That seems to work. Through a receiver but everything is really close? More tricky, but still very standard.
A projector 30 feet away?
Remote located sources?
Multiple displays?
Splitting?
All of these items are a nightmare in the 4K/60 world. Quality gear remains extremely expensive and cheaper gear is questionable in terms of both reliability and if it works in the first place. Tons of people are making claims of 18Gb/s support, which don't measure up in the real world. But, the biggest issue seems to be the cabling. The cabling, the cabling, the cabling! 18Gb/s is about 5 times what 1080p needed. It's much faster than what home networks support. It's beyond the rated capabilities of Cat-6 cabling (not really in shorter distances!). So, to make 18Gb/s cables, they are working right on the edge of what works.
Now, multiply all this 4K garbage by 2.5x to get 48Gb/s which is the HDMI 2.1 standard for 8K video and just hang your head in shame for even considering this post.
Not really, but you get the idea. While I think the HDMI 2.1 specification for 48Gb/s has some level of finalization, they don't have equipment to certify 48Gb/s cables at this point to that specification. Any gear rated to 48Gb/s isn't actually HDMI 2.1 certified. Not like HDMI Premium 18Gb/s cables are. And those already have issues. So, we are still phenomenally early in the 48Gb/s game. Anyone who considers that pathway at this point is playing on the bleeding edge, and they will be let for money as well as actual blood and tears over these next few years.
Spend half as much now on 4K. Wait five or six years, then pay the same amount again and get 48Gb/s support that actually has some testing and quality behind it.
Or bleed.
Your choice.