I need an ad blocker for a MacBook Pro

I suggest that you go to the App Store and search for "ad blocker." Review the costs and features of the ones with higher ratings. Which one is going to work best for you is something only you can determine.

You also have some ability to control things from within Safari. Go to Settings>Websites>Pop Up Windows and make sure it's turned off for websites where you don't need it. Also, go to the bottom right where it says "When visiting other websites" and set it to "Block."

You should also check Settings>Websites>Notifications and set everything to Deny. At the bottom of the page, uncheck the box next to "Allow websites to ask permission to send notifications."

Are you talking about a browser. If so try Brave.