It's not "consent" as understood by GPDR and ePrivacy. You had no recourse not to give it, therefore it was not willing and informed.

Not true, you can leave the website. The website of course has to not track you until you don't leave.

Again, this is not deemed sufficient by GDPR. According to the law you can't condition the service you're providing on collecting unrelated (to that service) data.

The GDPR doesn't apply to US companies. While the FB has EU offices right now, they're there for convenience only. They can close them next month and stop caring about the EU law.

| they're there for convenience only. They can close them next month

Citation needed? Facebook gets revenue from their ad network, which is used by European business customers and targets European users. Therefore they need to comply with European law.

And if someone tags me in a photo?

Then they uploaded a picture they shouldn't have uploaded and the person who uploaded it should be sued (by you and possibly by Facebook because they broke the TOS that says you can only upload stuff that doesn't break the laws - and a photo of you that you didn't agree to be uploaded is against the laws)

No, it's part of the basic privacy protection laws that every EU coutry has had for decades. It's the same law that says you can't share videos taken with a dashcam if you're recording in the public.