I want to use proton for our family of 2, but we do not need all the features of the Duo plan -- we just want Mail and Calendar. It would be great if we had sort of a "Mail Plus Duo", "Mail Plus 2-Pack", or "Proton Duo Lite" plan at 5-6$/month for two people, as opposed to 8$/month for two separate Mail Plus subscriptions. The idea can be extended for more members.

No other plan as of the time of writing fits our need at an attractive price point.
* Proton Duo is 15$/month for two people, but we do not need most of its features.
* Business Mail Essentials is 7$/person/month, or 14$/month for two people, which is already more expensive than simply having two Mail Plus subscriptions, and is close enough to the Proton Duo price to not even warrant consideration.