The Surface Duo may have spent a long time in development, but that did not make the dual-display smartphone any more repairable than other Surface products. The displays and glass panels can be removed without taking apart any other components, but that is about as good as it gets for the Surface Duo.
https://www.notebookcheck.net/The-Microsoft-Surface-Duo-is-a-pain-to-repair.494282.0.html