A taller Xproto-L appeared on the site with support for thicker and longer graphics cards and ATX PSUs. Feels like it's finally time to order it. https://www.xtia.com.cn/store/products/686417 Don't have a CPU, or GPU, or an SFX PSU due to shortages though. :-)
The design purpose of the side panel is to provide mouse and keyboard and other devices to avoid plugging the devices that need to be used for a long time on the top.
If it is a temporary plug-in device that requires a TYPE C interface, we will recommend plugging and unplugging directly at the top IO
From another point of view, when designing this side panel, we did not have the ability to design and produce the circuit ourselves, so we used the purchased mature products directly. But we have now mastered the ability to design this circuit ourselves, so we have changed the standard IO structure to TYPE C on our XPROTO-ATX