Much like security, you pick your countermeasures in advance in the hopes of raising the cost of an attacker to penetrating your security. You're not anonymous. You're anonymous to an adversary with a given amount of technical/legal/intelligence/etc resources to bring to bear on deanonimizing you.
People will probably give you links which describe adequate methods for securing you against adversaries without $1,000 or equivalent amounts of brainsweat. If that's your adversary, there. May you execute properly.
If your theorized adversary is a nation state, pick another adversary. You're guaranteed to lose that fight in the long run. If you bid the price of your identity up to $5 million, they will counter with "We routinely pay that to kill mosquitoes" and mean that entirely literally.