As a highly skilled and experienced PCB designer with a strong background in mechatronics, I believe I can provide the excellent services you are seeking. Having worked on a variety of projects throughout my career, including those which required integrating multiple components and designing complex schematics with varying data interfaces, I am confident in my ability to handle your moderately complex task.
Specifically in relation to your project, I am proficient in using Altium Designer and am therefore capable of delivering the quality double-layered PCB you are looking for. Moreover, I have worked extensively with UART communication and have used GPS modules like the NEO-M9N-00B before, which closely aligns with your requirements.
Additionally, my ability to analyze and understand complex systems enables me to suggest and select appropriate components efficiently. Your satisfaction is my utmost priority, and I assure you that choosing me for this project will result in the successful completion of your HAT design to effectively communicate between your Raspberry Pi Zero and the GPS module. Let's exceed your expectations together!