Question Any thoughts about collaboration software?

[carlsson]

Server operating system version

Ubuntu 20.04.6 LTS

Plesk version and microupdate number

Plesk Obsidian 18.0.73 Update #5 Web Host Edition

Are there any good collaboration software that can be integrated with Plesk? Claude tells me Kolab Groupware and Zimbra Collaboration are good alternatives, but I'd like to hear an opinion from a real human.

Needs: Specifically collaborate on one mailbox. You should be able to leave comments, see who has answered and so on. I want to install it on my Plesk server.

Input appreciated!