MiamiHawkTalk.fans uses Discourse (https://www.discourse.org/), which has recently become the go-to for professional forums. It should have most of what everyone is familiar with. We’re self-hosting, so we aren’t paying $100/month.
For transparency, running the site will cost ~$5-20/month, plus the yearly domain renewal. That’s manageable and we should be able to run this without the need to have any “premium” status or donations.
If you have any questions regarding how to do something, or just suggestions, let me know. I’ll get top men on it.