Analytics dashboard for B2B SaaS (charts, exports, alerts)

We're a 12-person B2B SaaS and customers keep asking for 'a reports tab'. Scope: usage charts over time (we have the events table), per-account drill-downs, scheduled CSV email exports, and threshold alerts to Slack. Our stack is Node/Postgres/GraphQL; you'll add a reports service and a React dashboard. Design system exists (Tailwind). Please be the person who says 'that chart is lying' when it is.