Nowadays, ssh-keygen -t ed25519 is recommended but it is not the default (rsa remains) for backwards compatibility reasons. This is of course obvious for the keep or change usename way when it come to create a ssh key.
Also, I like the change username way by happyharrysco1. I expected this in the end:
BTW, before running the full process, I wander why sudo <command> never asks a password in my Pi as on Ubuntu (
And a last question: I recently read, maybe in a beginners tuto (I'm new to Pi & Raspbian), that changing usernane (pi to something else) would lead into some corner problems. I wander if any could develop on this. On my own I think to raspi-config GUIs (graphical text et full graphical modes as with my eyes I saw "pi" in them) which may be hard-coded in these tools. Please confirm and give other issues if ever any (I later met one, see below).
Best regards and thank you the RPF for this wonderful little board and hard'n soft brains in it.