increase limit of cards

I apologize. The information I was referring to changed. 8 is the limit for your device. You would have to get an iPhone 8 or later to get 12.

If you want to use Apple Pay with more than one device, you need to add your card to each device. To get started, choose your device below. After you set up Apple Pay on iPhone or Apple Watch, you can use your cards on the web in Safari3 on some Mac models, while signed in to iCloud. On Apple Watch Series 3 and later, and iPhone 8 and iPhone 8 Plus and later, you can add up to 12 cards on a device. On earlier models, you can add up to eight cards on a device.

The limit is not to force upgrade. It is all the device can handle.

You should be able to add 22 cards to Wallet.