Hello @Grioyofem88
My Swisscom is your personal account to check and manage your data and subscriptions. You can access your Bluewin Inbox from your My Swisscom account.
Regarding the possibility to add a foreign number to activate the 2FA, at the moment, a Swiss mobile number is mandatory.
However, after identification of the contract holder, a Swisscom agent should be able to add a foreign number.
Hope it helps!