Nothing "new" is revealed in "private revelation" that is necessary for salvation.
Of the thousands of reported Maran visions/messages over the centuries, for instance, only about eleven have received approval from the relevant Vatican offices, and that is simply the outcome of investigation which has, to the best of anybody's ability, ruled out fraud, psychosis, or other natural causes.
Nobody --- not even the personal recipient of a reputed "private revelation" --- is obliged de fide to believe in a private revelation.
And it's considered "private" even if it was seen by 70,000 people, as at the "Miracle of the Sun" at Fatima, Portugal in 1917
You're welcome.
Think about what you just wrote. Do you see what you're saying?