The honest framing: running your own network is genuine ownership, and ownership comes with responsibility that a Facebook group does not carry. Both halves of that are true.
What ownership gives you: your rules, your branding, your revenue, your data, and the ability to leave. The network is yours to run, not a tenancy inside someone else's platform.
What it also means: you decide what is allowed and you handle what your members post. Nobody upstream is making those calls for you.
Areas worth getting advice on before you launch:
Your obligations toward the personal data of your members, which depend on where you and they are located
Your responsibilities regarding content that members publish
Tax, invoicing and consumer-protection rules if you charge for membership
Whether your community involves minors, which changes several of the above
We can tell you how the platform works. We cannot tell you what the law requires of you — that depends on your jurisdiction, your audience and what your community does. Speak to your own advisor.
A practical first step: write your community rules, and publish a privacy notice telling members what you collect and why.