Support

No. This has nothing to do with what LoginGuard is supposed to do. I would also say that you will probably not find any extension that can do that because it's a bad, impractical and impossible to implement idea:

• The email sending functionality for password resets is hardcoded in Joomla's com_users code. While a developer could conceivably write a plugin to also send an SMS message it would not be able to only send the SMS message instead of the email.
• Joomla requires a 32 character long alphanumeric code for resetting passwords as a matter of security. It would be impractical to send it by SMS and ask the user to type it.
• Overriding Joomla's password reset is conceivable with some trickery in some, but not all, circumstances. In this case a misguided developer could conceivably replace the reset token with a short lived, six digit code BUT this would make all accounts on the site susceptible to SIM swap attacks and plain old guessing (you'd have 2-10 minutes to guess the 6-digit code which is plenty of time). The reason this is not a massive issue for 2SV is that 2SV is used on top of a username and password not instead of.

So even if you could I would say that 100% you should absolutely and definitely NOT think about implementing such a feature. It would essentially replace all passwords with a 6-digit PIN which is trivial to hack. I understand what you had in mind but the law of unintended consequences applies very strongly to your idea. Sorry :(

No problem :) Have a great day!