Your biggest attribution gap is channel definitions. Right now, 42% of your sessions are bucketed as "Direct" or "Unassigned" because GA4's default channel rules don't recognize your traffic patterns. On top of that, your UTM tagging is incomplete on Meta Ads and Klaviyo, and payment processors are showing up as referral traffic.
I've highlighted the 3 most impactful issues below. Click any to investigate further.