Southeast Asia’s banks are at a pivotal juncture, transitioning from decades-old legacy cores to modern platforms built for the digital age. Most banks in the region still run on aging technology – 90–95% of banks rely on on-premises, mainframe-based cores averaging 20+ years old [1,2]. Only a small minority operate fully cloud-native cores, mainly among digital-only entrants [1]. These systems are expensive to run and hard to change, making modernisation a strategic necessity [1,2].