There is no easy solution. You are up against the basic terms of use of the system since you now reside in the USA and that is therefore your "home country".
The sections below are copied from the USA Apple Media Services Terms and Conditions document but I suspect they are very similar for all versions of this document --> https://www.apple.com/legal/internet-services/itunes/us/terms.html - Last Updated: September 16, 2020
"Our Services are available for your use in your country or territory of residence (“Home Country”). By creating an account for use of the Services in a particular country or territory you are specifying it as your Home Country."
"Terms found in this Agreement that relate to Services, Content types, features or functionality not available in your Home Country are not applicable to you unless and until they become available to you. To see the Content types available to you in your Home Country, go to the Services or visit https://support.apple.com/en-us/HT204411. Certain Services and Content available to you in your Home Country may not be available to you when traveling outside of your Home Country."
You can set up two accounts but you will need payment methods that are acceptable which means respective kinds billed to you at an address in each country.
From: Payment methods that you can use with your Apple ID; click here --> https://support.apple.com/HT202631
"Make sure that the billing address for your payment method matches the billing address for your Apple ID. In some cases, you might need to call your bank or financial institution to authorize international or online purchases. You might also need to confirm that the mobile number associated with your payment method is correct."
You apparently can use a card issued in a different country but it has to be billed to you at an address that is in the country to which your iTunes and App Stores are set. This requirement makes it unusual to be able use a card from a different country since card companies may be reluctant to issue a card unless the customer's address is in the card company's country.
Note, however, that the article may be in error as suggested by an Apple recommendation for a post saying, "You need a valid credit card issued by a bank in the country the store is in..." This is despite a post quoting the above section from an Apple document. - https://discussions.apple.com/thread/253211481
Each time you sign in and out of a country's store you will have to fulfill the full requirements of doing this which will include cancelling all subscriptions and waiting for them to expire. Apple used to have a waiting period between country changes but I don't see that anymore. Still...
Change your Apple ID country or region - Apple Support