Passwordless (magic login links is another term) is a great idea, but using a QR code just really breaks down the process and makes things a lot more difficult. Would be better to use a 2FA/MFA process instead, but at the very least passwordless/magic link is the way to go.
@Soni you seem to be convoluting different processes like Whatsapp uses to bridge a gap between a mobile-only service and a viewport on desktop. That really wouldn’t fit into this use case / flow here in a forum. You’re more thinking of a 2fa solution where you use a mobile device with an app like Google Authenticator or Auth0 Guardian or Authy to verify the login process that you initiate on a forum/app.