default mailadres on iOS, ipadOS

How can I change the default mailadres from an iPhone, ipadOS, MacOS?

Even if its possible to use an other mailadres like google the default will mostly be iCloud. I want to hide my account from the rest of the world but Apple doesn't feel they urge to this.

Recently there was a changing wind to use a temporary adres. This is a good step forward, and on MacOS it is almost possible to make it default. When I want to react quick on a mail I always need to think to hide my iCloud account name, keep it safe. Thats why I always use an alternative and not the standard on any OS from Apple.

Is it somewhere possible to fix this default matter? Or should I remove or never use the default cloud mail and use a Google, app, adres in combination with a browser full of rules. Make a bundel of rules, forwards and filters to help this solved...