How about an old keypad mobile or even a new one without inserting sim cards be considered for this purpose?
Theoretically, this is possible, but practically, being paranoid, I would think about this solution 10 times.
The fact is that the main function of a SIM card is subscriber authentication in the cellular network. That is, even without a SIM card, the phone can work (with some reservations), for example, calls to emergency numbers, like 911 (which are most often built into the GSM standard).
I can find some keypad mobiles that are brand new and available for under $50 - and $40 can do the job.
And I can find it completely free in a box of old mobile phones in my closet.
Availability is everywhere, we do not need to worry about the data stored getting deleted like calc and data dictionaries.
This is undoubtedly an advantage, as is the ability to add a password to access phone data.
This seems to be a good idea if you ask me, the old ones do not have any internet connections and only come to live as when a SIM card is inserted, they can be used for the purpose as you can save messages as text on drafts.
Old phones, unlike new Chinese push-button phones, don't have built-in backdoors and dubious apps that send data to their servers, therefore, it is better to use older mobile phones.
The text can be saved anywhere, from a notebook, a calendar, to a contact list. Limitations depend only on imagination.
