I currently do this with mailbox .org, I spend 4 euros a month for 2 accounts (3+1). This allows us to use the same domain, share storage and sync calendars. Mailbox also stacks up pretty well against proton in security and privacy just doesn't have a free plan and some of the little extras. It also supports catchall and full filtering if you really wanted to save the extra euro and use one account.
I currently do this with mailbox .org, I spend 4 euros a month for 2 accounts (3+1). This allows us to use the same domain, share storage and sync calendars. Mailbox also stacks up pretty well against proton in security and privacy just doesn't have a free plan and some of the little extras. It also supports catchall and full filtering if you really wanted to save the extra euro and use one account.