We have been building lists of undesirable and malicious addresses longer than almost anyone. We started with our CYBERsitter
product 26 years ago, blocking adult and other age inappropriate content for family computers. We've learned a lot about maintaining lists over the years.
IT professionals know that every device exposed to the public side of the internet gets bombarded by thousands of malicious bad actors daily. Unless you have considerable experience in fighting back against these intrusions, you are basically playing Russian roulette and hoping the next bullet is a blank.