From a compliance POV it's not enough. For example: "<NAME PERSON ONE> is president of the United States" is still identifiable even though the name has been redacted.

Since you can't be 100% certain that a filter redacts all personal data, you'd have to make sure that you have measures in place which allow OpenAI to legally process personal data on your behalf. Otherwise you'd technically have a data breach (from a GDPR pov).

And if OpenAI can legally process personal data on your behalf, why bother filtering if processing with filtering is also compliant?