“I don't know why you want the referral code thing here — it just gets all of the attention. Put it somewhere under 'cancel anytime' or somewhere that doesn't get that much attention.”

Move promo/referral code fields off the main paywall — they steal attention from the CTA

A referral or promo code input on the main paywall creates a cognitive detour: users who have no code wonder if they are missing a discount, and users who do focus on entering it instead of tapping the CTA. Move it below the fold, under the CTA, or into a secondary flow. The same applies to overly visible 'have a promo code?' links.