Hey Tederdmann,
Updating the contact number on the account would not affect any number you have set up for the 2 step verification. That can only be updated directly through My Shaw. You can find directions on how to do that here https://bit.ly/3cB1Wei. If you no longer have access to that old number, you can get in touch with our tech support and we do have the ability to temporarily disable the 2 step verification so you can log in to update that.