Could you help me understand what the problem is with this config? I would like to have bcachefs with tiered storage between hdd and nvme, but after deploying with nixos-anywhere, the system won't boot.

{ inputs, ... }:
{
  imports = [
    inputs.disko.nixosModules.disko
  ];

  # Enable bcachefs support in kernel
  boot.supportedFilesystems = [ "bcachefs" ];

  disko.devices = {
    disk = {
      # NVMe SSD - Fast tier for metadata and caching
      nvme = {
        type = "disk";
        device = "/dev/disk/by-id/nvme-SAMSUNG_MZVLB256HAHQ-000H1_S425NX2M363531";
        content = {
          type = "gpt";
          partitions = {
            ESP = {
              priority = 1;
              name = "ESP";
              size = "512M";
              type = "EF00";
              content = {
                type = "filesystem";
                format = "vfat";
                mountpoint = "/boot";
                mountOptions = [ "umask=0077" ];
              };
            };
            # NVMe partition for bcachefs (fast tier)
            main = {
              size = "100%";
              content = {
                type = "bcachefs";
                filesystem = "main_bcachefs";
                label = "nvme.main";
                extraFormatArgs = [ "--discard" ];
              };
            };
          };
        };
      };

      # HDD - Bulk storage tier
      hdd = {
        type = "disk";
        device = "/dev/disk/by-id/ata-WDC_WD5000AAKX-60U6AA0_WD-WCC2EU003365";
        content = {
          type = "gpt";
          partitions = {
            # HDD partition for bcachefs (storage tier)
            main = {
              size = "100%";
              content = {
                type = "bcachefs";
                filesystem = "main_bcachefs";
                label = "hdd.backup";
              };
            };
          };
        };
      };
    };

    bcachefs_filesystems = {
      main_bcachefs = {
        type = "bcachefs_filesystem";
        extraFormatArgs = [
          "--compression=zstd"
          "--background_compression=zstd:15"
          # Tiering configuration
          "--background_target=hdd"
          "--foreground_target=nvme"
          "--promote_target=nvme"
          "--metadata_target=nvme"
        ];
        subvolumes = {
          # Root filesystem - equivalent to @root
          "@root" = {
            mountpoint = "/";
            mountOptions = [
              "noatime"
            ];
          };

          # Nix store - equivalent to @nix
          "@nix" = {
            mountpoint = "/nix";
            mountOptions = [
              "noatime"
            ];
          };

          # Persistent data - equivalent to @persist
          "@persist" = {
            mountpoint = "/persist";
            mountOptions = [
              "noatime"
            ];
          };

          # Backups directory
          "@backups" = {
            mountpoint = "/var/backups";
            mountOptions = [
              "noatime"
            ];
          };
        };
      };
    };
  };

}

First, Now I've noticed that during the deploy I get:

Caution! After loading partitions, the CRC doesn't check out!
Warning: Invalid CRC on main header data; loaded backup partition table.
Warning! Main and backup partition tables differ! Use the 'c' and 'e' options
on the recovery & transformation menu to examine the two tables.

Warning! One or more CRCs don't match. You should repair the disk!
Main header: ERROR
Backup header: OK
Main partition table: ERROR
Backup partition table: ERROR

Invalid partition data!
Information: Creating fresh partition table; will override earlier problems!

Warning! Mismatched GPT and MBR partition! MBR partition 1, of type 0x82,
has no corresponding GPT partition! You may continue, but this condition
might cause data loss in the future!
The operation has completed successfully.
+ rm -rf /tmp/tmp.Befxfm9cFt
Connection to 192.168.68.103 closed.

First, Now I've noticed that during the deploy I get:

Caution! After loading partitions, the CRC doesn't check out!
Warning: Invalid CRC on main header data; loaded backup partition table.
Warning! Main and backup partition tables differ! Use the 'c' and 'e' options
on the recovery & transformation menu to examine the two tables.

Warning! One or more CRCs don't match. You should repair the disk!
Main header: ERROR
Backup header: OK
Main partition table: ERROR
Backup partition table: ERROR

Invalid partition data!
Information: Creating fresh partition table; will override earlier problems!

Warning! Mismatched GPT and MBR partition! MBR partition 1, of type 0x82,
has no corresponding GPT partition! You may continue, but this condition
might cause data loss in the future!
The operation has completed successfully.
+ rm -rf /tmp/tmp.Befxfm9cFt
Connection to 192.168.68.103 closed.

Back to your answer, It just hangs. No boot screen or anything

It could be the EFI partition since it doesn't show "Linux boot manager" (or whatever was it) in the boot menu.
That option is already set:

  boot.loader = {
    systemd-boot.enable = true;
    efi.canTouchEfiVariables = true;
  };