There is compatibility utilities for the other plugins that haven't moved to a flat format yet like You-Dont-Need-Lodash-Underscore but reading into it my understanding is the strict peer dependency for these two is intentional because there's breaking API changes.
Eslint v9 forces a migration to a new "flat" config file https://eslint.org/docs/latest/use/configure/migration-guide
Projects won't be able to extend this eslint config in v9 until we move to the flat config format.
As of writing, attempting to install eslint v9 gives strict peer dependency errors for
There is compatibility utilities for the other plugins that haven't moved to a flat format yet like You-Dont-Need-Lodash-Underscore but reading into it my understanding is the strict peer dependency for these two is intentional because there's breaking API changes.