Outlook Add-in REST API deprecation

Question

We are retrieving the email and attachments using the oAuth token from getCallbackTokenAsync in office.js JavaScript library and sending the token to the web application to retrieve them from EWS (~/EWS/Exchange.asmx) using SOAP request similar to the approach shown in https://docs.microsoft.com/en-us/office/dev/add-ins/outlook/get-attachments-of-an-outlook-item

1. Could anyone please confirm that the deprecation of Outlook Rest API 2.0 will not affect the existing functionality. I am new to the Outlook add-in development and the documentation seems vast to digest.

https://devblogs.microsoft.com/microsoft365dev/outlook-rest-api-v2-0-deprecation-notice/

2. Do we need to register the add-in anywhere OR provide any permissions to the add-in specifically for getCallbackTokenAsync method to retrieve the token OR making the SOAP request to download attachments.