It is easy to disable notifications either in Opera's settings or in Android - why didn't you do that first?
Oh i didn't know it can be disabled
But most peoples don't know how to disable it and we had some student getting +18 spam because they pressed allow for no reason. There will be more websites that abuses notification to keep asking until they press allow if no protection implement.
@simplythebest Glad to hear that. I would also suggest you try a bookmark app to backup your bookmarks so next time you won't lose any. I use Bookmark Folder. It's free and simple to use and also allows you to import bookmarks from an html file.