And that changes my recommendation a little. If you love the customer experience—and I agree the thumbnail selector looks substantially more intentional than six disconnected listings—I wouldn't abandon it yet.

The reason today feels brutal is that we've actually solved most of the reusable system already. The hard pieces are done: one Related Colorways metafield, one shared product template, one Liquid selector, automatic current-color naming, and separate InterestPrint products preserved underneath. Once we identify why InterestPrint's 500 units aren't considered sellable by the storefront, that fix may apply to every InterestPrint product you build this way going forward.

So I would give the inventory issue one final contained troubleshooting session, not keep randomly changing settings tonight. And importantly, I would not modify the global InterestPrint location until we know exactly what that setting does to your existing products.

If we solve that last issue, your future workflow becomes essentially:

Sync each colorway from InterestPrint → optimize each product → assign same product template → add products to Related Colorways → publish → done.

That's absolutely worth having as a repeatable YBP system.

And there may be an even simpler answer hiding here: because InterestPrint itself supplied that inventory and fulfillment location, I'd like to compare one existing InterestPrint product on your store that is currently purchasable against Black Steel. We don't need to touch anything—we compare its variant inventory/location settings side-by-side. Whatever differs is very likely our answer.

That is the next thing I'd do rather than digging through more Shopify settings. Open one known-good InterestPrint product that customers can currently add to cart, click one of its variants, and show me the same Inventory section you showed for Black Steel. We can compare the two and look for the exact difference.

Ohhh — this comparison is useful. I see a meaningful difference between the known-good InterestPrint product and the pants.

Working InterestPrint product

Your existing product has only one Shopify option:

Size: XS, S, M, L, XL, 2XL, 3XL, 4XL, 5XL

Inventory is 500 and it sells normally.

Black Steel pants

The pants have two Shopify options:

Color: white
Size: 2XS, XS, S, M, L, XL, 2XL, 3XL, 4XL

Yet there is only one color value (white).

That makes the unnecessary Color option our strongest lead now. And it also explains why Spotlight is rendering that bizarre struck-through:

Color → white

followed by every size being unavailable.

But I wouldn't delete Color yet because Shopify may rebuild the variants when an option is removed, and I don't want to risk the InterestPrint connection.

Let's do one very safe test first

Go back to InterestPrint and look at the original Black Steel synced product.

I want to know whether InterestPrint itself defines these pants with:

Color + Size

or whether Color = white only appeared in Shopify after syncing.

If InterestPrint shows the product as having 2XS–4XL sizes only, then we've likely found our culprit and can figure out the safest way to remove that redundant Shopify Color option.

If InterestPrint itself shows white / 2XS, white / XS, etc., then we leave that structure alone and continue looking elsewhere.

The good news is the comparison tells us InterestPrint inventory itself is behaving normally: the working item also has ~500 units per variant. So I would definitely not touch the global InterestPrint location settings.

We're narrowing this down without risking the rest of the store now.