How we read ecommerce ROAS before scaling spend
We start from the store system, not the ad dashboard alone. Shopify, Magento, WooCommerce or PrestaShop shows the actual orders, product mix and UTM trail. GA4 shows purchase events and attribution. The ad platforms show reported conversions. The work is to reconcile those sources before deciding what deserves more budget.
From there, margin changes the media plan. High-margin products and low-margin products should not receive the same target ROAS. Recent purchasers should usually be excluded from new-customer acquisition and moved into upsell or cross-sell flows. Creative also has to scale with budget; more spend usually makes fresh creator-led angles more important, not less.