It’s easy enough. Just use an old laptop at a public wi-fi location, and start from scratch there, including creating a new gmail account.
Then only use that location and that laptop for your “nefarious” stuff. At that point they would need security camera footage of you at the location or around it. That is not much of a concern - yet. When it becomes one, disguises are cheap and easy. Even a “dreadlock attached” baseball cap and sunglasses go a long way. If you’re really paranoid, wear a plaid logging shirt and stuff a pillow into it.
Don't forget that when your laptop or phone accesses a public WiFi (at, for example, a Starbucks), that your device's MAC address (which uniquely identifies your laptop) is part of the handshake to the WiFi router.
While the MAC address does not go out on the internet, it is possible that the public router may log it (and for businesses that offer "free" wifi service, it probably DOES log it (in case law enforcement comes calling with a request, because so many people use "public" wifi for doing things they want to keep hidden).