Must a person already own an Apple device to get a Apple card?

Apparently, yes.

From: How to apply for Apple Card - Apple Support

Requirements to get Apple Card

To get Apple Card, you must meet these requirements:

• To be eligible to apply for Apple Card, you must be 18 years old or older, depending on where you live.

• You must be a U.S. citizen or a lawful resident with a valid, physical U.S. address that's not a P.O. Box. You can also use a military address.

• Your device must be compatible with Apple Pay. See which devices are compatible with Apple Pay --> Devices compatible with Apple Pay - Apple Support [Apple devices only]. Make sure that your device has the latest version of iOS, watchOS, or macOS.

• You must sign in on your device with your Apple ID and use two-factor authentication.

• If you have a freeze on your credit report, you need to temporarily lift the freeze to apply for Apple Card. Learn how to lift your credit freeze.

• You might need to verify your identity with a Driver License or State-issued photo ID.5

Read the document for details.

You can apply without a device, but you’ll get only a line of credit in the Apple Store. And, you need an iPhone to request and activate a physical card