It sounds like your granite needs to be properly cleaned, which might include a poultice to get those stains out and then it needs to be sealed to prevent future staining.

Another thought is that you might be using too much granite cleaner creating a film layer and it is attracting/holding dirt in the areas that get used the most.

What stone is it? Not all "granites" should be sealed - most Absolute Blacks, for example, should not be sealed. Very dense stones will not take up sealer. If they are sealed, the sealant will often sit on top and create a "haze" over the stone.

On the other hand, less dense stones usually need to be sealed at least annually, sometimes every 4 to 6 months.

Which do you have?

I don't know what poultice to use, but Chispa is right. Maybe some stone experts will chime in (although, sadly, we don't seem to have many of them on the Forum anymore 😔).

Try searching on the kitchen forum for old posts that discuss stain removal, poultice applications and stone sealers.

Also try baking soda and water.

Are you sure it's granite and not some other stone? I find it odd that the things you mentioned have caused dark spots.

You need a poultice. There are lots of different types. Google and experiment please.