Cancel the card and apply for a different credit card. The terms and conditions you agreed to when you applied and accepted the account, specifically state you must have a required device (iPhone or Apple Watch). No exceptions.
The T&C went on to state that lacking a required device you are not eligible for an Apple Card Mastercard account and have only an Apple Store account. Apple Store accounts are limited to the purchase of Apple products and services. So, technically you are in violation of the terms and conditions and your account may be closed by Goldman Sachs Bank at anytime.
There is nothing way to get another card. Even if you ordered a replacement, your original card would be deactivated as soon as you activated the replacement.
If you don’t want to risk having your account closed, use the card and purchase an iPhone. Otherwise, you’re treading on thin ice in my opinion.
https://www.goldmansachs.com/terms-and-conditions/Apple-Card-Customer-Agreement.pdf