Ask HN: Recommended (ideally free) project community chat

I'm currently working on a project that needs a place for contributors and users to chat. Ideally something that is free, at least until the project is large enough to pay for a larger plan.

We definitely need a slack-like model to separate topics because it will ideally have both technical discussions around the project as well as a place for moderators and ideally even normal users to talk.

Itd be cool™ if it also had something like a forum/kb system and in a perfect scenario even a project planning component.

I've self-hosted Mattermost in the past and it went really well, but I would sort of like to avoid hosting yet another system if I can avoid it.

The project is currently not opensource, but we do plan on doing that at some point and could probably expedite that if it helped get us a free community plan.

We are currently using Zulip and while I do like it, its quite foreign to most users and I think thats harming peoples' ability to get involved. For non-technical users the slack model is already daunting and the Zulip one seems like its just too much.