We had an internal instance of ZNC for human users to connect their clients to (at their option - but that was the documented and preferred way of getting onto the IRC network). Creating ZNC user profiles was part of the semi-automated onboarding/setup procedure, whilst ZNC authentication was done against the dovecot IMAP/SASL server we had for email. More casual IRC users in the company (marketing etc.) usually preferred to use an intranet-hosted web application (The Lounge) to access it from their browser, while most IT people had native clients of their choice set up (hexchat, irssi, etc.). Worked well.