The aviation industry is currently facing the challenge of achieving net-zero carbon emissions by 2050, as future regulations would have it. However, conventional "tube-and-wing" architectures are reaching a plateau in efficiency, driving the exploration of disruptive energy sources and airframe configurations. Liquid hydrogen has emerged as a strong contender for sustainable flights, but the requirement for large cryogenic tanks typically leads to "dry wing" configurations (lacking the structural relief of fuel weight) and increased fuselage volume. To counteract these penalties, ultra-high-aspect-ratio wings are being investigated. Specifically, the Strut-Braced Wing (SBW) configuration is a key enabler for these slender wings, providing the necessary structural support to increase span and reduce induced drag without the weight penalty of a standard cantilever design. For that particular concept, research within the NASA SUGAR framework demonstrated that these configurations could achieve over 50% reduction in energy use when combined with advanced propulsion [1]. Additionally, previous work by the authors found that SBW concepts can outperform current aircrafts with respect to mission block fuel, without a substantial increase in MTOW, ultimately leading to configurations with up to a 15% reduction in mission block fuel [4]. Overall, most studies underscore the need for high-fidelity structural modeling to account for complex phenomena at every scale [2]. This paper details a comprehensive MDAO study of a commercial LH2 SBW aircraft, building on the framework detailed in previous work [3], which was extended to incorporate two major contributions: i/ advanced composite sizing of both the wing and the strut, with the intent of maximizing the weight savings offered by modern materials; ii/ explicit integration of the propulsion system, with a dedicated analysis of the interaction between the propeller slipstream and the wing aerodynamics. The resulting, new, optimized concept is then compared to a reference A320 type aircraft, as well as the result from previous studies by the authors [4]. Results will give insights into the trade-offs between aerodynamic efficiency and structural weight on the overall performance of the aircraft, as well as demonstrate a significant leap in fuel efficiency.