You have a valid suggestion but if you used your mobile, your private key is still on your clipboard, unless you're the type that deletes clipboard contents regularly

but if it hapens to be a brilliant hacker, I'd have looked into your clipboard, copied everything, then delete

but I'm nice, I won't do that, except for life and death situations or national security concern

and...

there's a way to recover deleted clipboard contents 😊

so yeah, check your clipboard first

on your mobile, tap MESSAGING

tap CREATE A MESSAGE

There's your keyboard!

and voila!

There's your clipboard!