Hello,
When I want to use Yahoo! mail with Brave browser then Yahoo! show me a message about ad-blocker and ask me to switch to the basic mail. I must refresh the page, but this message appears again after some minutes:
Can I disable it with “Inspect” feature?
You want to block the div tag with the modal-outer ID: #modal-outer. Otherwise, you are only blocking the individual message, and will need to do so again later.