Surprising that end-to-end encryption doesn't really matter when you get into one of the ends.

Even if you had to input your private key every time you wanted to read or send a message, having malware in your phone voids practically any form of encryption, because it has to be decrypted eventually to be used.

not at all. there is no encryption that can save you when one of the legitimate participants is somehow compromised. doesn't even need to be a sophisticated device compromise, literal shoulder surfing does that too.