I've long wanted something similar to this. I currently use Linear as both an ATS and a CRM, and most project management can be reduced to People/Companies, Tasks/Deals, and Pipelines.
Linear is not quite flexible enough for what I need as it is too strongly in the task management camp, so I can't define a proper candidate pipeline without hacking what the "status" of each "issue" means and remembering that.
Most small companies don't need dedicated solutions for project management, ats and crm, so I'd love to combine them. But I'd be looking for something more lightweight than this, maybe even local without cloud, but at least single service with sqlite or similar.
Would be amazing if it was very customizable to let people build or customize their own pipelines from some basic building blocks, still keeping the slick and fast UI from Linear.
I agree going after Slack at the same time is too ambitious.