Hi Again!
There can be if you do too many (Airbnb tracks this). You might contact Airbnb Customer Support and explain that the guest hasn't responded to your questions/you're concerned their profile is not complete/you don't feel comfortable hosting them. They may be able to decline for you and not have it effect your decline rate. I would at least ask them?
I believe guests can request again, unless you hit the three dots on the right side of a message (hover over message and the dots will appear). This will block any further requests from any "unsuitable guests" . Otherwise they may keep sending requests.
Reporting and Blocking a Guest
https://www.airbnb.com/help/article/2020
"If you block someone, they won’t be able to send you messages, use Instant Book for your listings, send you a reservation request, or accept a reservation request from you."
Decline a Trip Request
https://www.airbnb.com/help/article/360
Let us know what happens 😊