If you're using functional cookies, you don't have to ask. If you're still asking, you're just wasting your time.
The reason every website asks is because:
1. They're stupid and don't even bother to preliminarily research the laws they comply with.
2. They actually are tracking you.
Ultimately if you're using something like Google Analytics, then yeah you probably do need a banner. Even if it's just a blog.
Great, so then don't do that.