Yes that was the same with me. After the customer support was called, they resolved it today .

Have redeemed my keyboard from the Samsung shop just now! Y'all can try as well!

Yup I have 5g too, but the banner for checking eligibility and redemtion isn't available right now. The support keeps saying to not use wifi till I redeem the key oard but I think it's a way to delay the answers. As no one has got the redemtion yet.