Dual e-sims (2 different countries) w 2 different country App Stores - IPhone 15 Pro and iOS 26

My understanding is that the dual SIMs let you have different phone numbers but the entire iPhone is signed in under your one account and it is that which determines the app store that is used. You can sign into the App Store with a different account for that alone, but again you can only use a single country's app store at any one time. Anything that is on your phone from the old country will remain but cannot be updated or re-downloaded unless you set the account to that country.

Basically I have seen many posts like yours and there is no good solution. With Apple you either live in one country or you live in a different one and what you do is entirely associated with a single country at any one time. You can change country settings but it it has various stipulations which make it tedious to do frequently: Change your Apple Account country or region - Apple Support