Don't add amdgpu, actually remove amdgpu.
AMD has drivers in the kernel. I'm waiting for thread editing permissions here, I need to edit my guide. To simplify it even more, or complicate more
I had installed amdgpu-install_6.2.60203-1_all.deb which automatically added both of those. It doesn't pull in the driver which is as you say a kernel module already included (thank god they don't do dkms). It just pulls in some tools I think. I can remove it anyway.
I wouldn't be able to advise you of Linux command line magic. My knowledge goes as far as the best duck duck go search result
But, yes, swapping 6.3.4 to 6.4 should do it
If just updating the sources fail you probably have to update the gpg key 1st. I kept amdgpu as a source even though I'm not using dkms maybe additional firmware updates pulled from there. I tend to error on the side of caution.
Tax day so I'm folding from Win and from what I'm seeing there really isn't any performance penalties incurred for folding on Linux, as always ymmv.
I switched to 6.4 on Debian 12. The installation went smoothly but initially FAH couldn't see my GPU anymore. It turns out that 6.4 has no rocm-opencl-icd-loader which provided the symlink libOpenCL.so -> libOpenCL.so.1. So to get it to work I had to do this:
Either way works, but the "standard" is for the less specific library names to symlink to the more precise ones, like libfoo.so -> libfoo.so.x -> libfoo.so.x.y.
The best solution is for AMD's packages to include the symlink natively like they did in 6.2.3. I don't know why they removed it. Surely they tested their own package before releasing it.
It is not harmless
I've done enough fiddling with AMD related .so files to pick few snags along the way. Symlink it to original file which is .so.1.0.0 in the same x86...GNU directory
And let's not talk about why they removed stuff compared to previous rocm versions
It is a miracle they listened to me to include rocm-opencl-sdk within 6.3.4 and now 6.4