I work professionally in furniture rendering.
A large part of my workflow involves rendering the same furniture model with multiple materials and color variations.
At the moment, whenever I want to adjust a material after checking the render, I have to leave the render window, use the Material Picker to select and apply a new material, and then return to the render window to continue reviewing the result. Repeating this process over and over significantly reduces workflow efficiency.
If supporting the entire Asset Library inside the render window is difficult, it would already be a huge improvement if at least the Material Picker could be used while viewing the render.
Being able to select and modify materials without leaving the render window would greatly streamline the workflow and significantly improve productivity, especially for professionals who frequently iterate through different materials and color variations, such as furniture rendering.