Yea, view-once features in apps are mostly an illusion that’s oversold.

We have something close to some sort of an actual view once thing at work… it involves controlled access into secure rooms with no windows, lawyers, NDAs, security takes your phone and whatnot kinda deal.

A self destructing message is better than nothing, but hardly a guarantee

I memorize the seed and calculate the next token in my head.

Passwords in KeePass, totp in Aegis.
My phone does have both, but they each have their own encryption.