His existence never erases Anakin balancing the force. He creates Snoke and turns Ben into Kylo Ren. That creates the new imbalance that results in Rey being a new Chosen One.
If Palpatine created/manipulated the people who broke the balance, then that means his survival did nullify the balance that Anakin was supposed to bring. If he’s alive, even barely alive, then the Sith still exist and nothing about the imbalance has changed.