Is there anything that guarantees against scandal after engaging in foreplay to adultery while naked in a place that might be filmed by hidden cameras, with the fear of the matter being exposed to family and relatives?

You must repent to Allah with sincere and pure repentance. If you repent, Allah will forgive you and conceal your sin. And whoever fears Allah - He will make for him a way out from all that troubles him. So, turn away from whispers, attach yourself to Allah, and have a good opinion of Him. Increase your supplications for Allah to conceal you in this world and the Hereafter.