don't use gmail yahoo outlook and so on, the authorities now easily spot keywords and will be able to track you up in a few days. today there are tuta.io it will do. if you are paranoid like me create your own self hosted mail server, this is what i unfortunately have there are some constraints.
first of all, it's not free unless you have a server that runs locally and then if you don't have reverse dns (ptr), your emails will easily fall into spam on well known providers such as outlook, gmail and others...
now let's go back to the so called "anonymous" providers as tuta.io, you are not immune to these being indicators for the government. the world is big but in 2026, the world is on file everywhere. don't be surprised if one fine morning, the cops ring your doorbell. everyone has their own method, long live you