you've resolved the issues by now, since I see you posted two months ago.
That said, I got two, similar instant-bookings (1 trip, 0 reviews) and I have my Instant-booking settings at must have * identity verified and *good track record. Apparently "good track record" now means no negative reviews (and no track record, in the normal sense of the word, ie repeat history, is necessary) 😕 . I also remember the one awful guest I had several years ago, airbnb suggested neither of us review the other... so when I see zero reviews, I think "not good."
Now that the definition of "good track record" (odd as it is) is clarified, and I'm clear that my settings were wrong, I'm frustrated, and have simply turned off Instant-book for everyone. I suggested that airbnb fine-tune the "good track record" definition, or offer a couple levels we can opt in/out of, rather than having to turn off Instant-book.
re: your ratings, call customer service, ask about the odd instant-book that you didn't expect. Say something like, "since the person has no track record, has no reviews nor profile info, I feel unsafe having them come to my place." (safety is a powerful word) and " how do I cancel the booking without it affecting my ratings, since this person instant booked and doesn't seem to follow the guidelines?
That said, sometimes I've had new-to-the-platform bookings, we exchanged a few messages, and the visit turned out great. But them providing some info and sense of their character is key.
good luck next time.