That’s not the way they would track you. If you use the same email address for both accounts, a data broker on the back end will be able to connect them because you used the same email address. It’s not about the IP address. It’s about your identity. And if you’re like oh well I’ll just make a new email for each site, Gmail requires that you use a phone number to sign up. Most email providers do. So then they would just connect you by your phone number because you needed to use those on both email addresses. Privacy is nonexistent on the web. Mind you this happens because LinkedIn shares your data with “third-party partners and service providers”. There’s nothing that you can do to stop this.