I’m pretty sure if I accidentally press “OK”, I get charged extra. In addition to the pop-up, I get the same thing as a permanent notification until I reboot – if I try to disable the notification, I get “These notifications can’t be modified”, as it is using the built-in system SIM Toolkit. I am using GrapheneOS. Name and shame: MOVISTAR.
A different provider would probably work. Unsure about the other ones here. I believe root is required to disable Sim Toolkit pop-ups or notifications.
Or be the same problem. Best to check before. My experience where this is done is that all providers tend to do it. Naturally there may be exceptions.
Have you tried dev mode settings? I definitely remember having more granular permissions over notification controls after toggling something in there,though I forget what.
The grapheneos forums may be able to help you as well.