Before You File a Bug Report Please Confirm You Have Done The Following...

• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I have searched for related issues and found none that matched my issue.
• I have read the FAQ and my problem is not listed.

Playground Link

https://typescript-eslint.io/play/#ts=5.9.2&showAST=ts&fileType=.tsx&code=C4TwDgpgBAysBOBLAdgc0QZwBZQLxQwRVSgB8oBXZAEwgDMUJqypkKAbdoA&eslintrc=N4KABGBEBOCuA2BTAzpAXGYELm5AAgC4CeADigMbQCWphAtCvNQHaED0LA9vdIgCawW-AIZt6JcvQpcWyQtUKxEbVBgDakRNGhdokALq4AviGNA&tsconfig=N4KABGBEDGD2C2AHAlgGwKYCcDyiAuysAdgM6QBcYoEEkJemy0eAcgK6qoDCAFutAGsylAGYBDVCXTgwAXxCygA&tokens=false

Repro Code

type StringLike = string | undefined | null;

ESLint Config

module.exports = {
  parser: "@typescript-eslint/parser",
  rules: {
    "@typescript-eslint/no-redundant-type-constituents": ["error"],
  },
};

tsconfig

{
  "compilerOptions": {
    "strictNullChecks": false,
  }
}

Expected Result

No error (either by default like before or via additional option)

Actual Result

undefined is overridden by string in this union type
null is overridden by string in this union type

Additional Info

There are a lot of repos not using strict type checking but trying to transition to it, so adding | null or | undefined to the places where it's necessary takes a lot of time, especially when it's not done on a per-file basis where you can use a TS plugin.

Would be great to be allowed to have an exception for that, or have them ignored by default like until 8.47.0.