In the face of accelerating technological advancements and evolving customer expectations, banks worldwide are under immense pressure to transform their operations and improve service quality. This study investigates the role of digital transformation in enhancing service quality through a comparative case analysis of two banks: Hanseatic Bank in Germany and De Volksbank in the Netherlands. Hanseatic Bank emphasizes technology adoption, cloud migration, and open banking integration, while De Volksbank focuses on organizational restructuring and agile, customer-centric operational models. Using qualitative analysis of transformation frameworks such as Atlassian-based digital ecosystems and the Org Topologies model, the paper explores how these approaches improve service delivery, internal efficiency, and responsiveness to market demands. Furthermore, the research contextualizes these findings within the Vietnamese banking sector, which has demonstrated strong digital ambitions through strategic initiatives such as Decision No. 810/QĐ-NHNN of State Bank of Vietnam in 2021. The study highlights how banks in Vietnam can benefit from a hybrid transformation model that combines technological innovation with organizational agility. The paper concludes by emphasizing the necessity of fostering a digital culture, investing in infrastructure, and rethinking governance models to achieve sustainable service quality improvements in the digital era.