You’ve looked at the purchase history info article (the Related Article linked above), so I’mm assume this is a charge for an Apple service and not something purchased elsewhere using Apple Card, and that billing and subscription information is where to investigate this for charges from Apple.
If it’s one of the usual cause for duplicate charges (here parallel charges of the same amount, really), there’s a second Apple ID involved here somewhere, and the charges are arising from that; two Apple IDs, each with an iCloud+ subscription or an Apple One subscription or such.
You might end up discussing this with Apple Support, if you can’t find a subscription associated with another Apple ID of yours. Use the Get Support link in the upper right of this webpage.