I believe the generated eslint.config.mjs contains a mistake.
typescript-eslint docs say to configure tseslint like this:
import eslint from '@eslint/js';
import tseslint from 'typescript-eslint';
export default tseslint.config(
eslint.configs.recommended,
tseslint.configs.recommended,
);
https://typescript-eslint.io/getting-started/
But I don't see tseslint.config() called anywhere?