This thread was about which carrier to choose. I must assume it is well known that there is little one can do when it comes to dealing with cellular service companies.
The problem is multi-sided. First is greed, plain and simple. They are not non-profit organizations. But more than that, they want to not just make a fair profit, but to squeeze out at much as they can. (We either live a life of service to others or serve ourselves. That's all there is. And don't deal with authoritarians.)
Second, is ancillary to that; is there a way to sell the personal information of customers to maximize even more profits? Most will do just that.
Third, is the system build to encrypt customer info in such a way that even a warrant cannot gain any information? Are all the calls encrypted in transmission?
It would be far better to take any necessary steps to protect one's self as much as possible. Here are some ideas. First, never use your normal persona for private stuff. Second, get something under a business name. (Do you have an off-shore, aka safer jurisdiction, corporation?) Third, pay for it through anonymous methods.
For instance, you can pay a homeless person to go into a store for you and buy a burner phone. You don't even have to show up on camera. The activation card can be bought in another area. Turn off the camera and as much tracking software as possible, and never ever use it where you live or work. Know someone who's going overseas? Pay them to buy something elsewhere.
There are ways, if you are careful.
The bottom line is to never use a smart phone if you really wish to be safe as much as possible. It may be okay if your everyday persona is no secret and you have GrapheneOS or similar. But not ever for anonymous processes. One cannot trust what one does not control.
So what about two different phones?