Apple is no way makes things easy for dual residency claims. Apps and media are regionally licensed, may have governmental restrictions, and the system design is such to strongly discourage people trying to work their way around regional restrictions. I have seen posts hundreds of times with similar issues and there is no simple solution.
One solution is a distributor can decide in which App Stores they will allow an app to be distributed. You can contact the developer of the SUV app and see if they will add their app to the USA store. Click on this link to learn how to contact an app developer --> https://support.apple.com/HT207959
Apple's system is such that if you are moving to another country you should change your account to that country's settings. The support article https://support.apple.com/HT201389 describes how to change your country setting on everything using your Apple Account, and the requirements and results of doing this. Changing store country is not a trivial endeavor. The system is designed to only facilitate doing this if you are moving to the other country to take up residency. It makes it difficult for people to temporarily change country settings to do things such as get around regional distribution restrictions only allowing them to buy items available in the country where they actually live.
Using a separate account will have its own complications in setting it up (needing a payment method for that country, and an address, and a telephone number) and: https://support.apple.com/118412
‘When you try to associate a device that was previously associated, you might notice a message that says, “This device is associated with another Apple Account. You cannot associate this device with another Apple Account for [number] days.” You might need to wait up to 90 days to associate the device with a different Apple Account.’
If you set up a second account then you won't lose data on the iPhone if you do things correctly, but what will then happen is each time you switch accounts all data from one account will merge with data from the other account.
