@Christin4961
I haven't seen any official policy from Airbnb about text on photos except for Experiences. They do mention embedding links, or codes that take guests off platform in messages. I have seen many Listings with text on photos, QR codes to a listing walk-through video, etc. I do find some of the photos with text distracting, but if done correctly, it doesn't look bad.
I will say that Vrbo has a very stringent policy on this, and the will prevent you from even uploading a photo to the listing if it has text on it, even if it's just a sign (like Hot Tub Rules, etc.)
I guess to get a firm answer, one would have to contact Airbnb directly, but not sure you will get a correct answer. The other option would be to go ahead and try it. It would be most effective if on the cover photo, as that is what guests will see when scrolling. I would just not make the text so large that it obscures the cover photo, or make it too garish with stars or emojis.
Here is the help article that talks about not embedding links in messages:
Off Platform Policy
https://www.airbnb.com/help/article/2799