Information and communication technology (ICT) is crucial for enhancing organisations' economic, environmental, and social sustainability, while Enterprise Architecture (EA) supports developing and managing organisational ICT resources. However, since established EA standards and frameworks are primarily deployed in the context of developed countries, there is a need to understand the unique cultural, institutional, and resource constraints developing countries face in implementing EA. This empirical study investigates EA's current practices and challenges in developing countries, specifically Bangladesh, to support sustainable digital transformation. The research contributes to the EA understanding and sustainable digital transformation through literature analysis and interviews with professionals from diverse industries. The findings highlight a lack of understanding of EA among organisations striving to integrate environment, social and governance (ESG) factors into sustainability and ICT deployments. This study offers implications to research and practice related to challenges in practising EA in developing countries to support digital transformation and sustainability.