Make overrides in haskellPackages.developPakckage depend on each other

I have the following flake.nix

{
  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-21.11";

  outputs = { self, nixpkgs}:
     let
      pkgs = import nixpkgs {
        system = "x86_64-linux";
      };
      in
    {
      devShell.x86_64-linux = with pkgs; mkShell {
        packages = [
          (let
              http2-grpc-haskell-repo = fetchFromGitHub {
                owner = "factisresearch";
                repo = "http2-grpc-haskell";
                rev = "baf8e7cf8c58d9ab6004dedda089bd6492f25393";
                sha256 = "gjOPn1BcysmzfIOJSxr8U9vxULecvJkiEph4bcC8XLI=";
              };
            in pkgs.haskellPackages.developPackage  {
            returnShellEnv = true;
            root = ./.;
            withHoogle = false;
            overrides = self: super: with haskell.lib; {
              http2-client-grpc = doJailbreak (pkgs.haskellPackages.callCabal2nix "http2-grpc-haskell"
               (http2-grpc-haskell-repo + "/http2-client-grpc") {});
              http2-client = doJailbreak (markUnbroken super.http2-client);
            };
          })
        ];
      };
    };
}

If i run nix develop I get

error: Package ‘http2-client-0.10.0.0’ in /nix/store/3g25cg20m43hvsy17d7nz0jxwk79a77w-source/pkgs/development/haskell-modules/hackage-packages.nix:145064 is marked as broken, refusing to evaluate.

       a) To temporarily allow broken packages, you can use an environment variable
          for a single invocation of the nix tools.

            $ export NIXPKGS_ALLOW_BROKEN=1

        Note: For `nix shell`, `nix build`, `nix develop` or any other Nix 2.4+
        (Flake) command, `--impure` must be passed in order to read this
        environment variable.

       b) For `nixos-rebuild` you can set
         { nixpkgs.config.allowBroken = true; }
       in configuration.nix to override this.

       c) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
         { allowBroken = true; }
       to ~/.config/nixpkgs/config.nix.
(use '--show-trace' to show detailed location information)

If i depent on http2-client-grpc in the cabal file. If I only depend on http2-client it isn’t marked as broken anymore. How can I get http2-client-grpc to depent on my overriden `http2-client\

It should work if you replace pkgs.haskellPackages.callCabal2nix with self.callCabal2nix.
self is haskellPackages after applying the overrides. callCabal2nix picks the dependencies from the haskellPackages you took it from.