So here is the feedback.
1.- While I was waiting for the letter with the code that I had been forced to request to activate 2FA (also forced to “opt” as explained before) the email login allowed me in the meantime to simply click on “ finish later” (see screenshot below) and, therefore, we had the whole family access to email, nothing more, in complete independence.
2.- Then, I received the letter; but I didn’t want to enter the code and activate 2FA. The code is now outdated.
3.- Today, when I login and the system asks me for the phone number for 2FA I have the option to simply click on “ignore” (as before) (see screenshot below).
So this is what we will continue to do so that each member of the family can access the email without having to chase the person who receives the code on their cell phone.
It’s not great, but it’s all Swisscom allows me to do (until the next crisis 🙄)
THANKS!