Big GPU cards support with M.2(pcie)?

is it possible to connect and user big gpu cards over M.2 slot ?
and can nvidia share supported/tested boards for nvidia arm linux drivers.

The GPU driver in the existing Jetsons are for hardware directly integrated with the memory controller. External GPUs use PCI, and thus require different drivers. The only arm64 drivers out there are for what are essentially data warehouse devices, and not compatible with a Jetson. So you are out of luck. A lot of people have talked about it, and I think there has been some discussion of making some of those arm64 drivers for PCI available on Jetsons, but as far as I know this has not been done yet, and nobody has ever said anything about committing to do so in the future.

Are you working on nouveau drivers??
It will be nice to have drivers working on some SBC as raspberry pi or some amlogic boards

Nouveau is incompatible with NVIDIA drivers. I suspect Nouveau would also require a GPU which is going through PCI instead of direct integration with the memory controller. You can be guaranteed that if you get a Nouveau driver working, then the NVIDIA GPU will be non-functional.

Yes, I am talking about RTX 2000/3000 working on SBC like raspberry pi :) It will be really nice to have it working.
For example I would like to use video encoder from nvidia cards and SBC for network connection.
Or coin minners would also be happy :)