So, there are apparently 31 offers on the listing. In a case like this, there may be no BuyBox or if there is one, it is given to a FBA seller. It is unlikely you will get the BuyBox with so many other listings.
Amazon’s algorithm considers factors like price competitiveness, fulfillment method (FBA usually has an advantage over FBM), account health, seller metrics (order defect rate, late shipments, and feedback score), and inventory availability. If your price is higher than competitors, your fulfillment method is less preferred, or your seller metrics are not strong enough, Amazon may not grant you the Featured Offer. To improve your chances, try lowering your price, switching to FBA if possible, ensuring fast shipping, and maintaining excellent seller performance.