I like that tuta is doing just one thing, ( ignoring the new storage feature ), and trying it's best at it.
Proton is going to more of a google approach, however the nonprofit goal they just set is pretty awesome.
I got the tuta's, now non-existent, premium plan, and am using simplelogin relays to protect it. No plan in changing the setup.
Nowadays proton owns simplelogin and I think it offers it's services to customers, a couple bucks cheaper than my impossible setup, so protonmail it's probably the best option nowadays.
I think the POSIX standard only has one root user, however many users can have root privileges.
So it's probably a trick question, however any user even without privilege can make create a file which others can't, read even the root itself I think not sure though.
Yeah and try to load a custom OS into anything other than an computer is a nightmare, just last week while trying to install twrp recovery and flash a custom ROM which I been doing for quite some while hard bricked my phone, mad ended up fucking it completely by trying to fix it with mtkclient.
Take my upvote and kindly get out. Please.