Well, you still haven't told us what this is for.

But with 20 game consoles involved, with only 1 output.... into an AVR....
The practicality of what you are trying to do, is certainly a VERY niche purpose. Which 100% means you are going to be using 'specialty' products to accomplish the task. That automatically means "not cheap". Period.

Also: If you are going to try and push 48Gbps (4K HDR, 4:4:4, 120Hz), you will likely fail at anything you try to cobble together. You just can't go thru multiple devices with a signal like that and succeed. At least the chances are slim, with today's technology.
It's hard enough getting a signal like that to go thru just an AVR to a monitor, with an extender involved. Throw in a large HDMI switching device.... I don't know, current experience tells me you are going to have to use something more like 4K 4:2:0 60Hz, to get what you want accomplished.