Is there any way to use this application without logging in with microsoft / mojang account?

[qtlich]

Is there any way to use this application without logging in with microsoft / mojang account? Is there a way to use offline account? What can I do to achive this?

[terrarier2111]

There should now be a very easy way to do this using mojang's minecraft launcher and the installer for leafish that's provided in releases you can simply add an offline account after launching leafish from a launcher of your choice (Mojang's launcher or Prism)
if you don't want to login to any account for security reasons you can also run leafish headless (by just executing the leafish binary that's available in the "Downloading a pre-built version" section in the readme)