Five numbers, same order every month: leads by source, cost per lead by paid channel, close rate on the prior month's leads, median speed-to-first-response, and new reviews. Write them next to last month's. The comparison IS the report.
Then one decision: what gets more money or effort next month, and what gets less. A report that changes nothing is a ceremony; the monthly reallocation is the whole point of measuring.
If an agency writes your report: it should lead with those business numbers, not impressions and clicks. Activity metrics (posts published, keywords tracked) belong in an appendix, if anywhere. You're paying for outcomes, and the report should be organized around them.