For a number of years now, the most active FoC channels have also been bridged to Matrix rooms. This was made possible by a Slack <-> Matrix bridge operated by the Matrix.org Foundation, but unfortunately the bridge will be decommissioned early next year (https://matrix.org/blog/2025/11/removing-slack-bridge/). If you happen to know anyone who may have been making use of this bridge to participate in this community, please encourage them to re-join via Slack directly. (I'll try to contact the ones I know of as well.)