Hi there,
ReadonlyArray is regarded as Array in array-type rule. Similarly, readonly T[] is regarded to be the same as T[].

• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I have read the FAQ and my problem is not listed.

Repro

Here is an example of 'array'.

{
  "rules": {
    '@typescript-eslint/array-type': ['error', {
      default: 'array',
      readonly: 'array', // 'array' | 'generic' | 'array-simple'
    }],
  }
}

const foo: ReadonlyArray<string> = [];

Expected Result

4:12  error  Array type using 'ReadonlyArray<string>' is forbidden. Use 'readonly string[]' instead  @typescript-eslint/array-type

Actual Result

4:12  error  Array type using 'Array<string>' is forbidden. Use 'string[]' instead  @typescript-eslint/array-type

Additional Info
#4066

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