@Eoin8 your acceptance rate would have to drop very low for Airbnb to block your calendar, but excessive declines could impact your placement in search results.
Acceptance rate is not among the superhost criteria:
https://www.airbnb.com/help/article/829/how-do-i-become-a-superhost
Response rate is, of course. Don't ever fail to respond.
In your shoes, to minimize the necessity of declining, I would make your guest requirements excruciatingly clear in your listing and pre-booking message, telling people to please not request to book if they don't meet them; and then if someone still requests to book without meeting those requirements ask them to withdraw their request.
Many hosts operate very successfully and comfortably without instant-booking.