Subscription businesses can't judge ads on the first payment. A channel with a weak first month can be your best if its subscribers stay a year.
BrainyMetrics groups payments into subscriptions automatically from Stripe, GoHighLevel, PayPal billing agreements, systeme.io and ClickFunnels plans, or the API. The Subscriptions report shows active subscriptions, MRR, new and churned subscriptions and rebill revenue by first-touch channel. Custom events like trial_started can be marked as conversions too.