Good ghostwriting should not suddenly make you sound like a completely different person.
If somebody who knows you reads a post and thinks, "They would never say that," the writing has probably missed the mark.
The aim is not to disguise the existence of a writer through tricks. It is to make sure the finished work genuinely reflects your ideas, experience and way of communicating.
That becomes easier when a ghostwriter has enough material to understand your voice and when you provide honest feedback during the early stages of the relationship.
Over time, the editing process should become lighter as the writer becomes more familiar with you.
Ultimately, the most convincing writing is not convincing because nobody suspects a writer was involved. It is convincing because the ideas and voice genuinely belong to the person publishing it.