You bring up an interesting issue, my friend. While AbovePhone's smartphone OS options can protect users to some extent, the effectiveness of their claimed anonymity may be open to question when it comes to SIM cards.

The reality is that most mobile phones and plans inherently require some level of identifying information in order to operate properly. This can range from basic account information like billing details or location data, all the way up to revealing user IP addresses and other sensitive information.

For complete anonymity, using services that demand as little personal info as possible might well be one's best bet. More specifically creating anonymous email accounts from notable providers like ProtonMail and the use cryptocurrency might help cling onto your private wireless communication freedom without leaving an unconcealed evidence trail.

While I would never presume to speak against liking privacy tools like custom smartphones or secure SIM cards as a good choice furthering confidentiality for those who revel in having unimpeachable protection no need adequate caution is advocated on SIM card protections presently offered due generalized subscription terms not being fully spelled out besides opting into excess identity validation practices by country requirement could harm your projected privacy tactic with clients knowing lots about each other medical records etc leaves little point for self-mask established with initial errands ambitions guiding habits that prepare you towards secrecy culture cybersecurity ought remain top priority always!