This is what they write themselves:

https://www.facebook.com/about/privacy

It's says "we store data for as long as it is necessary to provide products and services to you and others."

That is super vague, it could mean they could still for example, keep my information to provide birthdays gifts as ads to my mother?

It also mentions, the things they delete: "such as your photos and status updates." But they build a profile of you including buying information from 3rd parties. So they'll keep that, It's feel creepy that they get to keep all that metadata.

To conclude "Keep in mind that information that others have shared about you is not part of your account and will not be deleted when you delete your account." Does that mean, if 1 person shares my phone-number with facebook that is oke? I'm not sure what I gain from the fact they have that information.

I'm a EU citizen, how does that work, it feels this still conflicts with GDPR and next to that, how will they EU enforce this, is some Bob going over the facebook and go through all their databases looking for traces of people that removed their account? who decides how much information can they keep about me? How much data can they keep while still making it impossible for them to point it back to me.