Log In - via SMS Passcode (OTP)

The goal from this is to allow users the ability to login to there cabinet via sms passcode. Users will be able to register or sign in solely with there phone number. A passcode is to be sent every time the user signs in. Hence, no more users signing in with a email or password. Firebase by Google allows this for a free cost plan. There is a plugin that I use for over a dozen websites that I manage and users are able to login to a wordpress site via sms passcode. Many are out there, but the one thats been very useful and filled with lots of improvements over the last 4 years using. It is called Digits / https://codecanyon.net/item/digits-wordpress-mobile-number-signup-and-login/19801105?srsltid=AfmBOor-ARZ2irvAYDTC7LRO_3DCAuYDBbv0frYe351cZGN5jfvH9hF_