Im not sure how I missed this post! Your right, GrapheneOS is definitely an amazing ROM! Thanks for mentioning it.
For anyone who just wants to get away from monitoring/tracking of their phones I always recommend LineageOS because it is compatible with many more different phones unlike GrapheneOS, which can only be used with the google pixel like you said. Getting rid of google and the bloatware gets rid of the tracking/monitoring so IMO lineage is perfectly fine if someone is aiming for this aspect and just wants their privacy back.
But I agree with you 100%, if someone wants to go that extra mile if they are trying to hide content on their phone.. than GrapheneOS is the way to go. Shitty thing with Lineage is that it keeps your bootloader unlocked... which makes it vulnerable if someone were to physically get your phone. This would allow them easier access. Graphene locks the bootloader again once its installed which is very impressive and their encryption is top notch!
I am also a huge advocate of Veracrypt and use it on all my PCs as well. Another great program worth mentioning!
Correct sir LineageOS is the more "friendly" but still much better secure OS. GrapheneOS is the shit hit the fan, full out paranoid mode if you enjoy going full security.
Veracrypt is great used them all the way back when they were TrueCrypt before things got weird. I don't think there's another FDE solution I'd trust other than the built in Linux OS one. wish more people would learn how to use GNUPGP etc to converse atleast for orders etc. There's great email providers out there now like Tutanota and Proton but in the end nothing beats PGP keys and hand doing it, then you can technically use whatever email provider you want and no one is reading that shit.