How to dis-associate from websites you used your steam account to sign up to?

Hi, I want to dis-associate from said websites. Not because of privacy or anything, I don't believe people care about any of my datas, I just want to do it because I want to.

But websites like trade websites don't have a "delete account" option because of how it merely operates on your steam identifier. However, I was wondering if I can cut my account connection from said websites by steam itself?