Connected Accounts, sending a reply or sends as the connected account the email stopped working

The connected account feature is for all practical purposes gone.

The configuration that i have used for years and worked for our users very well is now permanently non functional as it depended on connected accounts. The most important feature connected accounts provided was autoreply to set the From field on a reply when that was to a email associated with a connected account.

Each of the connected accounts was connected to a single purpose O365 shared mailbox. This has send as / on behalf of permissions. The user can manually set the from field but they routinely forget. Is there any feature / config or other setting that can auto set the from field on an reply?