As an enterprise user of Protonmail, I'd like to have more options for routing incoming email flows.

In particular, I'd like to be able (like Google Workspace, for example) to route non-existent email addresses (from protmain perspective) to an external MTA (an exchange server or similar).

This could enable a smooth transition (or long-term use) between a third-party email provider and protonmail users on the same domain name...