We have an NX Workspace with different Angular apps and migrated to NX 20.4.0 and Angular 19.x (below the specific libs):

    "@angular/core": "19.1.4",
    "@angular-eslint/eslint-plugin": "19.0.2",
    "@angular-eslint/eslint-plugin-template": "19.0.2",
    "@angular-eslint/template-parser": "19.0.2",
    "@eslint/eslintrc": "^3.2.0",
    "@eslint/js": "9.19.0",
    "@ngrx/schematics": "19.0.1",
    "@nx/angular": "20.4.0",
    "@nx/eslint": "20.4.0",
    "@nx/eslint-plugin": "^20.4.0",
    "@nx/js": "20.4.0",
    "eslint": "9.19.0",
    "eslint-config-prettier": "9.1.0",

Following the NX Docs we migrated the eslintrc.json configs to the new flat format with the command: nx g @nx/eslint:convert-to-flat-config

Everything went good, but now running a lint command triggers the following error:

 NX   Only URLs with a scheme in: file, data, and node are supported by 
the default ESM loader. Received protocol 'eslint-plugin-plugin:'

This comes from the root eslint.config.mjs file:

import { FlatCompat } from '@eslint/eslintrc';
import { dirname } from 'path';
import { fileURLToPath } from 'url';
import js from '@eslint/js';
import nxEslintPlugin from '@nx/eslint-plugin';
import eslintPluginCustomRules from 'eslint-plugin-custom-rules';
import eslintPluginPluginNxAngular from 'eslint-plugin-plugin:@nx/angular';  <---

const compat = new FlatCompat({
  baseDirectory: dirname(fileURLToPath(import.meta.url)),
  recommendedConfig: js.configs.recommended,
});

export default [
  {
    ignores: ['**/dist'],
  },
  {
    plugins: {
      '@nx': nxEslintPlugin,
      'custom-rules': eslintPluginCustomRules,
      'plugin:@nx/angular': eslintPluginPluginNxAngular,  <----
    },
  },
  {
    files: ['**/*.ts', '**/*.tsx', '**/*.js', '**/*.jsx'],
    rules: {
      '@typescript-eslint/parser': 'off',
      '@angular-eslint/prefer-standalone': 'off',
      '@nx/enforce-module-boundaries': [
        'error',
        {
          enforceBuildableLibDependency: true,
          allow: [],       
        },
      ],
    },
  },
  ..pat
    .config({
      extends: ['plugin:@nx/typescript'],
    })

The migration script generated the import path. I even tried to use: import eslintPluginPluginNxAngular from '@nx/angular'; but this then triggers another error inside the library in the node_modules:

 NX   Cannot find package '@ngrx/router-store' imported from 
.../node_modules/@nx/angular/fesm2022/nx-angular.mjs

Aside many people having different issues in migrating eslint to the new format, I could not find a solution to my issue. It seems to me a basic import/path misconfiguration but I cannot find a way to fix it yet.