> Losing keys.. 

So, you prefer to give your keys to a company that can do anything as if they were you... That is not safer or more private. The company can and is tracking you everywhere. 

> Metadata

DMs on Nostr don't leak metadata anymore. Just use the new one. It has been live for over a year. 

> IP address

Proton doesn't protect you against IP leakage. Every time you connect to any server, your IP leaks, including Proton's.