I'm doing something similar with an Office 365 business essentials subscription (~$5/month)
my main email address only has the most important stuff while everything else I setup a shared mailbox for.
then every shared mailboxes forwards anything received to an office 365 group called Catchall which i have available on the main address and i just need to switch mailboxes if I want to reply from it (you should be able to do this through mail.app afaik).
this allows me tighter control on a case by case basis and I get all the benefits of Office365 business.
this allows me tighter control on a case by case basis and I get all the benefits of Office365 business.