My question is if I buy an old iPhone from someone and then completely restart that phone and delete everything if I sign in with my new Apple ID, will the first iPhone owner have access to any of my privacy???
Use the following procedure for the old phone and no one will have any access to your information: What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support
Use the following procedure for the old phone and no one will have any access to your information: What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support
How to change ownership of iPhone after buying old iPhone???
