and if you use a VPN?
VPN won’t help at all, unfortunately, because it is something that is independent of your TCP/IP connection.
Imagine if I held a bright Red, Pink & Purple umbrella with distinctive stripes and polka dots. Then I don a mask (like using VPN). People won’t know who’s under the mask, but when they see the umbrella, they’ll know it’s the same person as last time: that’s what advertisers want to know. And they’ll be able to track you (okay, I mean your computer - not you as an individual) across websites unless you disable JavaScript.