Arabic support is more than swapping labels: layouts need to mirror for RTL, typography needs an Arabic font with the right line height, and dates and numbers need consistent formatting. I build the app to support translated content; the Arabic copy itself should come from a translator who knows your market.
Payments depend on your trade licence and bank: Network International, Telr, PayTabs, Checkout.com, Amazon Payment Services and Stripe are all common, alongside Apple Pay and Google Pay. Digital goods inside the app still need App Store or Play billing. UAE PDPL also makes data location, retention and consent worth deciding before launch, not after.