Technology selection is the key aspect and complexity of the solution architect's role. There is a broad range of technologies available, and a solution architect is required to identify the right ones for the solution. The solution architect needs to have a breadth and depth of technologies to make the right decision since the chosen technology stack can impact the overall delivery of the product.
Each problem can have multiple solutions and an available range of technologies. To make the right selection, a solution architect needs to keep functional requirements and NFRs in mind and define selection criteria while making a technology decision. The selected technology needs to consider different perspectives, whether the goal is the ability to integrate with other frameworks and APIs or to meeting performance requirements and security needs.
A solution architect should be able to choose the technology that not only satisfies current requirements but also scaling for future needs.