> In a corporate environment lack of e2ee is a deal breaker
Not in my experience. I would want a new hire to be able to search past history for context and to many businesses like to monitor the chats.
Keep in mind, IRC would generally be hosted by the business themselves so they’d have full access to the data. Why would that business want to hide their employees messages from themselves?
It is rare these days that company actually has their own physical server room and "cloud" by default is not secure - you have to rely on cloud company security and integrity.
I am thinking of that kind of scenario, however if you control who can access the servers then it may not be necessary.
Even still, e2ee isn’t desirable in the industry. See Slack and Teams, the most popular IRC replacements used in the corporate world. Neither are e2ee.