Supabase now has support for mobile/password and a one-time-password over mobile using a phone number and Twilio(?).

See:

{ email, phone, password, refreshToken, provider }: UserCredentials

Sign in now accepts:

async signIn(
    { email, phone, password, refreshToken, provider }: UserCredentials,
    options: {
      redirectTo?: string
      scopes?: string
    } = {}

and

  async signUp(
    { email, password, phone }: UserCredentials,

And if phone and password, then mobile/password -- if just phone, then OTP.

Likely. some UI will be needed to verify the OTP:

https://github.com/supabase/gotrue-js/blob/797ea09b6188291861b5bed4a488cc74b6f95aaf/src/GoTrueClient.ts#L222

Currently, the Supabase docs have not been updated with info on how to use, but expect these to be updated tis week (during the Launch Week).