Safest way to store texts and notes on a fully offline device

Jack2465

Does anyone know an application for a notes app with these characteristics:
-encrypted data (e.g. with wrapping key from Strongbox)
-option to clear all data (overwrite not only delete)
-installable and usable without an account on a device which was never online
(- the simpler the better. Storage of mediumsized texts is enough)

Any recommendations?

Probably9857

Standard Notes, maybe?

Jack2465 -encrypted data (e.g. with wrapping key from Strongbox)

With a passcode. See details here: https://standardnotes.com/help/79

Jack2465 -option to clear all data (overwrite not only delete)

SSDs don't work like that. Use Private Space or separate user profile. Delete the PS or profile if you want to make the data permanently inaccessible.

Jack2465 -installable and usable without an account on a device which was never online

Yes.