Linux mint is Free and Open Source Software (FOSS) meaning its free to use, and free to copy and modify. Open source means all of the source code is publically auditable so you can be assured it offers the privacy it claims. GrapheneOS is FOSS as well, actually you should only use FOSS if possible as closed source software is unverifiable in which you ought to assume any claims made about privacy are lies. This is the case for iOS for instance, Apple claims information like wallet data, iMessages and more are encrypted but you have no means of verifying this.
https://linuxmint.com/
