Holistic radio design emphasizes the importance of creating the radio as an integrated, cohesive system rather than as an interconnection of individual components. With the advent of sixth-generation (6G) technology, the proliferation of use cases and communication protocols demands evaluation across diverse scenarios and applications. Additionally, 6G will introduce solutions utilizing new spectrum bands, modified channel coding schemes, and energy-efficient waveforms. Evaluating these diverse test cases to achieve optimal radio design presents a significant challenge. To address this, we have developed a software-defined radio (SDR)-based flexible transceiver platform. This platform serves as a comprehensive and versatile testbed, enabling rapid exploration and assessment of various radio design configurations within a holistic framework. Its inherent flexibility allows for the configuration of both hardware and software components, facilitating the analysis of customized radio architectures tailored to specific use cases.Index Terms-software-defined radio (SDR), multiple-input multiple-output (MIMO), radio frequency (RF) transceiver, holistic radio design.