@ajsadauskas @asklemmy I've been self-hosting and also use my instance for my private IT business. From what I can tell it's built on owncloud and the the server commands use the occ command that references that codebase.
Key apps to check out:
Memories (for photos)
Deck (for Kanban productivity boards)
Mastodon Integration
Polls (Doodle Alternative)
Forms
Appointments
Talk (May need a high-end signaling server but can replace Google Meetup/Teams/Zoom/Slack)