it say you cannot change the storefront information for your account at this time
If you change Country or Region, you must comply with all regulations described here -> Change your Apple ID country or region
Change your Apple ID country or region - Apple Support (KW)
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That means:
You need to have a debit / credit card issued by a bank in your new country.
You need to have a billing address in your new country.
See also -> Payment methods you can use with your Apple ID
Payment methods you can use with your Apple ID – Apple Support (UK)
Rwanda
- Most credit and debit cards
fyi: Not all credit & debit cards seem to work with App Store / iTunes Store, try a different one, or preferably a credit card. If your card is not accepted as a paymenf method, you need to contact your bank.