Relevant part of my configuration.nix:

{
  config,
  inputs,
  lib,
  pkgs,
  ...
}:
let
  amdgpu-kernel-module = pkgs.callPackage ../../nixos_modules/patches/amdgpu-kernel-module.nix {
    # Make sure the module targets the same kernel as your system is using.
    kernel = config.boot.kernelPackages.kernel;
  };
  # linuxPackages_latest 6.13 (or linuxPackages_zen 6.13)
  # amdgpu-stability-patch = pkgs.fetchpatch {
  #   name = "amdgpu-stability-patch";
  #   url = "https://github.com/torvalds/linux/compare/ffd294d346d185b70e28b1a28abe367bbfe53c04...SeryogaBrigada:linux:4c55a12d64d769f925ef049dd6a92166f7841453.diff";
  #   hash = "sha256-q/gWUPmKHFBHp7V15BW4ixfUn1kaeJhgDs0okeOGG9c=";
  # };
in
{
  boot = {
    extraModulePackages = [
      (amdgpu-kernel-module.overrideAttrs (_: {
        patches = [
          ./0001-drm-amdgpu-mes11-optimize-MES-pipe-FW-version-fetchi.patch
          # amdgpu-stability-patch
        ];
      }))
    ];
  };
}

patch file itself, which can be found on the first AMD link:

From 2771f96336e3c469622f6e0e132f24ad1ba6a5c6 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher@amd.com>
Date: Thu, 27 Mar 2025 17:33:49 -0400
Subject: [PATCH] drm/amdgpu/mes11: optimize MES pipe FW version fetching

Don't fetch it again if we already have it.  It seems the
don't reliably have the proper value at resume in some
cases.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4083
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/mes_v11_0.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/mes_v11_0.c b/drivers/gpu/drm/amd/amdgpu/mes_v11_0.c
index 16f8bc36afa07..06b51867c9aac 100644
--- a/drivers/gpu/drm/amd/amdgpu/mes_v11_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/mes_v11_0.c
@@ -895,6 +895,10 @@ static void mes_v11_0_get_fw_version(struct amdgpu_device *adev)
 {
 	int pipe;
 
+	/* return early if we have already fetched these */
+	if (adev->mes.sched_version && adev->mes.kiq_version)
+		return;
+
 	/* get MES scheduler/KIQ versions */
 	mutex_lock(&adev->srbm_mutex);
 
-- 
2.49.0

forgot one other file needed. This one is amdgpu-kernel-module.nix, referenced in the configuration.nix as well. This is the part that packages the amdgpu module separately from the kernel:

{
  pkgs,
  lib,
  kernel ? pkgs.linuxPackages_latest.kernel,
}:

pkgs.stdenv.mkDerivation {
  pname = "amdgpu-kernel-module";
  inherit (kernel)
    src
    version
    postPatch
    nativeBuildInputs
    ;

  kernel_dev = kernel.dev;
  kernelVersion = kernel.modDirVersion;

  modulePath = "drivers/gpu/drm/amd/amdgpu";

  buildPhase = ''
    BUILT_KERNEL=$kernel_dev/lib/modules/$kernelVersion/build

    cp $BUILT_KERNEL/Module.symvers .
    cp $BUILT_KERNEL/.config        .
    cp $kernel_dev/vmlinux          .

    make "-j$NIX_BUILD_CORES" modules_prepare
    make "-j$NIX_BUILD_CORES" M=$modulePath modules
  '';

  installPhase = ''
    make \
      INSTALL_MOD_PATH="$out" \
      XZ="xz -T$NIX_BUILD_CORES" \
      M="$modulePath" \
      modules_install
  '';

  meta = {
    description = "AMD GPU kernel module";
    license = lib.licenses.gpl3;
  };
}

In reply to @niko:nyanbinary.rs
6.12 works