I am currently using Twilio as a messaging provider. I am using .NET 8 API with the Twilio Nuget package 7.0.1.
I am wondering whether I can keep the current SMS flow that I have:

Each client of ours has a dedicated phone number that they can write to. Based on an event in our system, I can also contact the client. Flow:
Event -> Client ID -> Get the unique Phone Number -> Send SMS
So we have a dual communication going on.
I was wondering, whether I can keep the same flow if we integrate Twilio WhatsApp. Based on the documentation here (https://www.twilio.com/docs/whatsapp/self-sign-up), can I use the already Active numbers that we have and Send either SMS or WhatsApp messages based on demand?
Or is it available with only one phone number when we integrate the Twilio Business WhatsApp profile?
Are all Phone Numbers that we already have and manage, portable to use WhatsApp and the sender name be the same - Company name?