eslint v8.57.0 (.eslintrc.cjs). Are objects in overrides isolated? i.e. rules in extends for files: [*.js] and for files: [*test.js] are not concatenating or they do?

[Dmitriy-Frostoff]

Current devDependecies in package.json

package.json is with "type": "module";
node: v21.7.1;
npm: v10.5.1;
VSCode: v1.88.0;
ESLint extension for VSCode: v2.4.4;
Prettier extension for VSCode: v10.4.0;
Format Code Action extension for VSCode: v0.1.0;

"type": "module",    
"devDependencies": {
    "@commitlint/cli": "^19.2.1",
    "@commitlint/config-conventional": "^19.1.0",
    "@types/jest": "^29.5.12",
    "@typescript-eslint/eslint-plugin": "^7.5.0",
    "@typescript-eslint/parser": "^7.5.0",
    "eslint": "^8.57.0",
    "eslint-config-airbnb-base": "^15.0.0",
    "eslint-config-airbnb-typescript": "^18.0.0",
    "eslint-config-prettier": "^9.1.0",
    "eslint-plugin-import": "^2.29.1",
    "husky": "^9.0.11",
    "jest": "^29.7.0",
    "prettier": "^3.2.5",
    "ts-jest": "^29.1.2",
    "typescript": "^5.4.4"
  }

Whatsap!) 👋
I couldn't find an answer all day long so decided to ask here...

• Q a): Please, can one clarify how does overrides objects interact with each other? Or they are fully isolated?
  E.g. i wanna to create a config file for usage with *.js, *.ts, *.test.js and *.test.ts files via specifying extends only for the current extension type in the overrides and to have a few common things(env and parserOptions) in main space. Yeah, it's a DRY violation but i wanna to have clear dependencies and ability to easily delete unnecessary ones...
• Q b): Is it awful idea to use the eslint config that way?
• Q c): will object with files: ['**/*.test.ts', '**/*.test.tsx'], extend plugins and parserOptions from the object with files: ['*.ts'],?
• Q d): Is it better to place 'plugin:jest/recommended' after 'airbnb-base', or leave at current position?

Of course, as only all the eslint packages mentioned above will move to flat config i'll use eslint flat config too)))
P.S. Thanks for all the goodness that you do to make the Programming World Better!!! 🙏🙌

current .eslintrc.cjs config (it's placed on the relative path: configs/eslint/.eslintrc.cjs)

const path = require('path');

module.exports = {
  env: {
    browser: true,
    node: true,
    es2024: true,
  },
  parserOptions: {
    sourceType: 'module',
  },
  overrides: [
    {
      env: {
        node: true,
      },
      files: ['.eslintrc.{js,cjs}'],
      parserOptions: {
        sourceType: 'script',
      },
    },
    {
      files: ['*.js'],
      extends: ['airbnb-base', 'prettier'],
    },
    {
      files: ['*.ts'],
      extends: ['airbnb-typescript/base', 'prettier'],
      plugins: ['@typescript-eslint'],
      parserOptions: {
        parser: '@typescript-eslint/parser',
        project: path.resolve(__dirname, '../ts/tsconfig.json'),
        ecmaVersion: 'latest',
      },
    },
    {
      env: {
        mocha: true,
        jest: true,
      },
      files: ['**/*.test.js', '**/*.test.jsx'],
      extends: ['plugin:jest/recommended', 'airbnb-base', 'prettier'],
    },
    {
      env: {
        mocha: true,
        jest: true,
      },
      files: ['**/*.test.ts', '**/*.test.tsx'],
      extends: [
        'plugin:jest/recommended',
        'airbnb-typescript/base',
        'prettier',
      ],
    },
  ],
  rules: {},
  noInlineConfig: true,
  reportUnusedDisableDirectives: true,
};