Sneaky folks seem to keep moving the location of the setting! After mucking about, I finally found the current one, as of August 2022:
Settings->Basic "Allow Acceptable Ads" toggle to off.

For those who need to find Settings, either:
-Click the gear in the left hand sidebar; or
-Click the sliders icon in the upper right "Easy Setup", just below the close-out X, scroll to bottom of pop-up menu "Go to full browser settings"; or
-Right click on any empty space on the start page, choose Settings

Basic is the top tab on the Left menu in Settings

Beneath Privacy Protection are:
Manage Exceptions
Manage Lists
Allow Acceptable Ads <- toggle that to off.

I don't mind developers making money through ads, but unwanted ads in my speed dial moves the icons around so I have to pay attention to them, which defeats the purpose of speed dial in the first place. Opera is still my go-to browser [has been since the browser wars] so it was worth finding a solution. But from what I can easily find, this setting keeps being relocated and re-named, probably to reduce the number of users opting out. That's a very, very, bad plan! People who use Opera are dedicated, but will jump to a different browser if Opera becomes annoying or just as big a resource hog as the other options. Stop playing silly games with your users!

Sneaky folks seem to keep moving the location of the setting! After mucking about, I finally found the current one, as of August 2022:
Settings->Basic "Allow Acceptable Ads" toggle to off.

For those who need to find Settings, either:
-Click the gear in the left hand sidebar; or
-Click the sliders icon in the upper right "Easy Setup", just below the close-out X, scroll to bottom of pop-up menu "Go to full browser settings"; or
-Right click on any empty space on the start page, choose Settings

Basic is the top tab on the Left menu in Settings

Beneath Privacy Protection are:
Manage Exceptions
Manage Lists
Allow Acceptable Ads <- toggle that to off.

I don't mind developers making money through ads, but unwanted ads in my speed dial moves the icons around so I have to pay attention to them, which defeats the purpose of speed dial in the first place. Opera is still my go-to browser [has been since the browser wars] so it was worth finding a solution. But from what I can easily find, this setting keeps being relocated and re-named, probably to reduce the number of users opting out. That's a very, very, bad plan! People who use Opera are dedicated, but will jump to a different browser if Opera becomes annoying or just as big a resource hog as the other options. Stop playing silly games with your users!