Shopify Multi-Step Pre-Checkout Upsell Funnel

We are building a premium Shopify store using the Dawn theme and are looking for an experienced Shopify developer to help us implement a multi-step pre-checkout upsell funnel.

We have already tested several Shopify upsell apps, but most only support a single upsell step, basic cart recommendations, or post-purchase funnels.

We need a genuine sequential funnel journey before checkout.

The exact visual format is flexible. It could be a popup, one multi-step modal, cart drawer, dedicated pre-checkout flow, or another suitable format.

The priority is the funnel logic and customer journey.

Required funnel flow

Step 1: Initial purchase

Customer adds the first bottle to cart at:

£27.99

The funnel should only activate when the relevant trigger bottle/product is present in the cart.

Step 2: First upsell

Customer is offered another/complementary bottle at:

£21.99

They should be able to either:

Accept the offer
Decline / skip the offer

Their choice determines the pricing available in the next step.

Step 3: Conditional next offer

If the customer accepts the £21.99 offer:

They unlock the next bottle at £17.99.

If the customer declines the £21.99 offer:

They can still be shown another bottle, but the price remains £21.99.

The customer must not be able to unlock the £17.99 price simply by declining the previous offer.

The £17.99 price should only become available after successfully accepting the previous £21.99 offer.

So the logic is essentially:

£27.99 initial bottle

Then:

£21.99 offer

If accepted: next bottle £17.99

If declined: next bottle remains £21.99

Final stage

After the main upsell sequence, we also want a final stage relating to additional household members / avatars / profiles.

This stage should allow the customer to continue adding relevant bottles for additional people before proceeding to checkout.

We are still developing the exact UX for this final stage, so we are looking for someone who can help implement the required functionality once the structure is finalised.

Core requirements

We need:

A genuine multi-step pre-purchase funnel
Funnel activation based on specific products being present in the cart
Sequential progression through the offers
Conditional logic based on whether the previous offer was accepted or declined
Different pricing depending on the customer's previous action
£17.99 pricing only unlocked after the correct previous offer has been accepted
Accept and skip/decline options
Ability to continue into an additional household/avatar stage
Smooth transition into the normal Shopify checkout once the funnel is complete
Compatible with the Shopify Dawn theme
Compatible with Shopify Grow
Fully responsive across desktop and mobile
Reliable cart and pricing behaviour
No interference with standard Shopify checkout functionality
Styling that can be customised to match the existing store design
Important

We are not looking for:

A standard bundle builder
A single-step upsell
A simple "you may also like" recommendation
A cart drawer that just displays several products at once
A single popup containing all the offers at once with no progression
A post-purchase-only upsell solution

The customer needs to be taken through an actual funnel journey, where the next stage depends on what happened in the previous stage.

The presentation itself is flexible: popup, modal, cart drawer, dedicated flow, etc., as long as the underlying experience is genuinely multi-step and conditional.