Lots of the newer stuff is watercooled

Yes they use pcie electrically, but its not the same slot shape and there is usually carrier boards

You wouldn’t repurpose these for home gaming, it would still be for llms

Indeed, also even the air cooled ones are designed for high static pressure fans (ie small fans that spin at really high RPMs). Those fans are really really loud.

You can just mod them to run on consumer fans that are designed to spin much slower but have higher diameter

would it be possible to sell this stuff to any of these "crypto" companies for mining or whatever tasks?