How to remove payment method from one device without removing it from all devices?

You can't. For that, you need to change your Apple ID on that device.

One Apple ID on Multiple Devices

Advantages:

• Convenience: Seamless experience across devices. Contacts, photos, notes, etc. are all synced. You only need to remember one login.
• App & Media Purchases: You can access all your purchased apps, music, movies, etc. on any device signed in with your Apple ID. No need to repurchase.
• iCloud Backup & Restore: Easy backups and restores of your device data to iCloud.

Disadvantages:

• Privacy: All data associated with your Apple ID is accessible from any device signed in with it.
• Mixed Data: If you use your Apple ID for work and personal life, data might get mixed up.
• Lost Device Security Breach: If you lose a device, someone with access might be able to access your entire Apple ID information.

Multiple Apple IDs

Advantages:

• Privacy: Separate data for work and personal life.
• Security: A security breach on one Apple ID wouldn't affect the other.

Disadvantages:

• Inconvenience: Switching between IDs for different purposes can be cumbersome.
• Double Purchases: You might end up buying the same app or media twice for different IDs.
• Family Sharing Limitations: Sharing apps and media purchases becomes more complex.

Choosing the Right Option

For most users, using one Apple ID across all their devices is the most convenient option. However, if you need strict separation between work and personal data, or are very concerned about security, then using multiple Apple IDs might be worth the hassle. Consider using Family Sharing on a single Apple ID to share some content while keeping other data separate.

iOS/iPadOS: Open the Settings app, tap on your name at the top, select"iTunes & App Store," tap on your Apple ID, select "View Apple ID," sign in if prompted, tap on "Payment Information," and then remove or update your payment method as needed.

Or change the Apple Id on that device because payment information will be link in both of your active devices.

Here is how to create an apple id

1. Open Settings: On your iPhone or iPad, go to Settings.

2. Sign in to your device: If you’re already signed in with another Apple ID, sign out first. Go to Settings > [your name] > Sign Out.

3. Tap “Sign in to your iPhone” or “Sign in to your iPad.”

4. Tap “Don’t have an Apple ID or forgot it?” and then tap “Create Apple ID.”

5. Enter your birthdate and tap Next.

6. Enter your first and last name and tap Next.

7. Choose your current email address or get a new iCloud email address. You will use this email to sign in to your Apple ID. Tap Next.

8. Create a password that you haven’t used before for an Apple ID. Confirm your password. Tap Next.

9. Select a security question and type the answer. Repeat this step for a total of three questions.

10. Agree to the Terms and Conditions and tap Agree.

11. Enter your credit card and billing information, then tap Next. You can choose None if you don’t want to enter payment information right now.

12. Verify your email address by entering the code sent to your email.

13. Tap Next to complete your Apple ID creation.