According to Finnish data protection ombudsman, data subject has right to object in case of legitimate or public interest. Data subject does not have right to object when it's based on contract or legal obligations.

https://tietosuoja.fi/en/what-rights-do-data-subjects-have-i...

Objection itself may or may not stop the processing of data. Usually it should, but there are some situations where it would still be allowed (e.g. "a task in the public interest that requires scientific or historical research or the compilation of statistics")

https://tietosuoja.fi/en/controller-s-legitimate-interests

Now I don't know if there has been any decisions or not based on what kind of tracking would actually be legitimate interest (the text on the website is very ambiguous)