First instinct: I would personally start with Nextcloud and then fill in the blanks. It covers a lot of ground, file sharing, collaborative document editing, calendars, contacts.

You don't explicitly mention some of these, but they're inevitably part of all businesses.

Odoo was the best self hosted ERP last time I looked (although it wasn't recent). IIRC it handles point of sale as well as online purchases. Best if you use it for inventory mgmt too. Some components are paid.

One of my favorite resources on the internet is https://awesome-selfhosted.net/ You'll find hidden gems in all the categories you listed.

Edit: actually, first instinct is to follow philomath_mn's advice and self host the minimum amount of services. Even with a small off-the-shelf NAS collecting video footage there's always some maintenance going on. This is a fine hobby, but can be a distraction from the real thing.