USB C cable doesn't work when connect macbook to non apple devices

Here are a couple of reasons why your USB-C to USB-C cable is not working with your non-Apple keyboard, yet it does with the adapter:

• Some USB-C to USB-C cables are designed primarily for charging or high-speed data transfer (e.g., Thunderbolt 3/4, USB4) rather than basic USB 2.0/3.0 connections.
• Many mechanical keyboards still rely on USB 2.0, and some USB-C cables don't properly negotiate power/data for those lower-speed devices.
• Some devices expect to communicate via USB-C's "downstream facing port" (DFP) vs. "upstream facing port" (UFP). The adapter might be helping by forcing the correct role.
• Your USB-C to USB-A adapter may be simplifying the communication, bypassing certain USB-C protocols that aren't working between your Mac and the keyboard.

Not sure how to best answer that question as it will depend on:

• The USB-C to USB-C cable you use. There are no less than nine USB-C cable "types," ranging from a USB 2.0 USB-C cable to a Thunderbolt 5 USB-C cable. To hopefully clarify a few things. USB-A, USB-B, USB-C, etc. are physical characteristics of the port/connector shape. USB 1.0 - 4.0, & Thunderbolt 1 - 5.0 are protocol standards (what those port types can support data and power-wise.)
• What the peripherals' USB-C port can support. I suggest that you review the manufacturer's specs for your USB-C peripherals to find this out. Typically, keyboards with USB-C ports only need a USB 2.0 USB-C cable.
• What your Mac's USB-C port can support.