Grapevine product managers

How hard is it to implement changing phone number for a profile, I can really help code it over a weekend if you tell what the stack is.

I do want to continue using the platform but don’t want to recharge 3600 just to be able to get OTP from grapevine, it’s like paying that much for recharge of a phone number which I don’t use just to be able to continue with this profile