Mate, I MANAGE Outlook in my enterprise environment.
Sure, I guess if you have some very specific add-ons as a requirement, it might be difficult. But these things are dying out, 99% of the time Outlook is being used only for email and nothing else. In such scenarios Thunderbird is perfectly fine.
Now, without MDM/DLP/IAM it's literally illegal to introduce Linux in many environments. Any business handling finances MUST be compliant to regulatory standards, and those require these systems to be in place. Without those three you lose your license and literally just cannot do business anymore.