This repository uses tslint which has been deprecated for 5 years https://palantir.github.io/tslint/
It also uses dtslint directly which has been deprecated and moved to a monorepo which has a disclaimer not to depend on any of the tools https://github.com/microsoft/DefinitelyTyped-tools/blob/main/README.md#disclaimer

The tslint maintainers point to typescript-eslint as a replacement and both https://github.com/tsdjs/tsd and https://github.com/JoshuaKGoldberg/eslint-plugin-expect-type provide the linting capabilities of dtslint as they are used in the immutable-js project.

Would you be interested in a pull request with a migration that replaces tslint and dtslint with eslint plugins?