First, something to keep in mind is that you choosing to use a privacy-respecting phone hurts Google, Apple and every cellular service provider's bottom line. They do not want you using degoogled phones, so it is possible that we will have to do a little troubleshooting to get the phone working with your carrier after you receive it. For most people, especially those just transferring an activated physical SIM card from their old phone, the process is usually like using any other phone and works seamlessly.

This phone is guaranteed to work with T-Mobile, AT&T, Verizon and U.S. Cellular and all of their MVNOs.

As long as you have a physical SIM that's been activated in a stock phone, you should be golden, and I've had success even activating lines on T-Mobile MVNOs in a degoogled phone. For other carriers, you might have to activate a new line's physical SIM in your old, stock phone.

The one exception is the AT&T MVNO PureTalk, who appear to have created some way to block any phone with a custom OS from working with their service, at least in the case of two customers I've had over the years. If you need AT&T, there is probably a better MVNO you could easily switch to with a little research.

Please keep in mind Verizon is easily the most difficult of the carriers to deal with when it comes to privacy respecting phones. If you are not willing to work through and troubleshoot issues that may arise, then a degoogled phone might not be for you. If at all possible, switching to one of the other major carriers or one of their MVNOs is highly recommended. T-Mobile is easily the best.