I love mattermost and use it on the daily.
I got it as a self hosted version of discord but I played around with the focalboard as well.
Being a project manager I felt it held its own against many of other SaaS overpriced project boards like Monday.com.
still needs some work though but I'd recommend it.
As far as chat mattermost does look like a very good Slack-alternative near-F/OSS alternative, but these days Matrix and Zulip are also very good. Did you happen to try those options/do a bakeoff?
As far as kanban/task management goes, Gitea/GitLab/GitHub feels like the right place these days (for software companies). Are there any reasons you prefer a standalone tool over putting the PM stuff a bit closer to the code?
