They definitely should be there, and if you want to set your own parserOptions, that would always be happening after extending configs, so it shouldn't cause any errors.

No @ljharb he's right; it's incorrect to set parserOptions.sourceType to "module" for every linted file, including .cjs files which are always CJS and, if the project package.json has type set to "commonjs" (which is the default!) .js files are also CJS.

Less concerning, but setting ecmaVersion: 2018 also seems like it should not be the concern of this particular plugin as ecmaVersion relates to more things than just ESM syntax. Only the user configuring their project can know the intended ECMA version for their codebase. It's not good this plugin's recommended config downgrades an ECMA version higher than 2018 that may have been set by other ESLint configs.

Order of config extends matters, and the end user should be setting these things anyways.

Separately, i don’t recommend using the recommended config from any eslint plugin, including this one - semver constraints mean it’s almost always not in an ideal state. You should be using this plugin via the Airbnb config.