As a Managed Service Provider (MSP), we are telling companies and their users to not use the New Outlook.
Since most of our clients use shared mailboxes extensively, this is a a feature that we cannot do without. And since hundreds of users already have shared accounts associated with them, we are not interested in a workaround that would create dozens of support calls, no matter how well outlined the steps and repercussions are.
Additionally, I personally attempted to do without the feature for over one month. I missed multiple important messages that had financial implications to the company. I really like the interface and was hoping I could use it going forward. Unfortunately, I switched back to Outlook 2019 today.
For the geeks out there: If you have multiple full featured email accounts and start an email under the wrong email account, in the New Outlook, you cannot just change the address, like you can in previous editions. You have to copy and paste the content or start over with a new message. This tells me that in the new Outlook the accounts have a barrier between them that is not managed locally. Perhaps an API driven architecture is being used. Either way, for me personally, this is a significant challenge, since I have multiple separate accounts for multiple separate companies in Outlook. I'd imagine users who have personal and business email managed in Outlook are experiencing the same issue. An issue that I am also sure is not limited to starting messages in the wrong account.
When I switched back, I was offered a survey of why I was reverting to my previous Outlook version. I noted the lack of functionality as the reason, noting the inability to add shared folder to favorites.