A facebook employee explained me how tracking works. Its not the email address Meta is concerned about. Its the IP, device identifiers and location. Meta doesnt care about the email at all apart from sending you emails for notification. Even with a fake email they exactly know who you are. Let's say you visit CNN.com which has facebook tracker. Facebook has the IP and the device identifiers. Now you login with fake email account on Instagram, facebook knows that's the IP ans the same device hence it "must" be the same person That's how facebook creates shadow profiles.
It's almost impossible not to have a unique fingerprint online with how stuff is tracked. Websites are tracking user agents, screen resolution, your GPU/web graphics renderer, etc.
The only way is to disable JavaScript, but good luck to using the internet without it
Never heard about Tor Browser? Nice "privacy" community you've got here.