If you're looking for something along the lines of SegMetrics, would make a shameless plug of https://www.ablecdp.com/ (I'm a founder)
While it doesn't calculate CAC out of the box, it's super-reliable for determining the sources of conversions, especially anything offline/recurring and, besides built-in conversion reports, provides real-time attributed conversions data in a easy-to-use BigQuery schema that's very handy to cross-reference with costs in Looker Studio
