Turn on "Advanced Account Security", that prevents model training from being turned on.
Adds the highest level of account security by requiring stronger sign-in methods and applying stricter protections to help prevent unauthorized access.
That is not about model training.
> Automatic training exclusion. People working with especially sensitive information may opt not to have those conversations used for model training. With Advanced Account Security enabled, that preference is automatic: conversations from those accounts will not be used to train our models.