Just pull out that old Nokia phone that has no camera or internet or anything, and buy a sim card from a supermarket or something, and do your thing.
That explains why I want to buy lot's of these old Nokia phones. I had doubts on why to use a new one each time.It's best to buy a new disposable phone while you're at it.
Phones have a serial number that is sent to the tower along with the serial number of the SIM.
If you've ever used "that old Nokia" with any other SIM before they are linked in a database forever.
"Remember, hacking is more than just a crime. It's a survival trait!" - Razor and Blade, Hackers (1995)
this ok if you are hiding from tax agencies , but for serious felony no internet protocol can minimize your risks to high limit .practically speaking it's very difficult for everyone - using VPN server (as a gateway to the internet) in country A using the sim card from operator based in country B in country C is pretty strong setup - SIM card in roaming uses local operator to find the way home and from there to your vpn server - if you choose the right countries and pay for the services the right way... good luck to anyone to track what and from where you're doing...
You should check out company called SecureCrypt SecureCrypt | Encrypted Communications Provider
They also offer anonymous SIMs, they provide a secured device with a custom built end-to-end encrypted chat/calling app which is a private app / no Google or App Store involvement. Very good. I use it, my associates use it. They’ve been around since 2018.