Yes, it works on Wayland.

Since Keyshift interacts directly with input devices, it’s independent of the desktop system, so it works seamlessly on Wayland, X11, and even in terminal environments.

Thanks for sharing your experience with input-remapper—glad to hear it’s working well for you! I wasn’t familiar with it before, but after looking into it a bit, here are some initial comparisons:

• Performance: Keyshift is built in C++ with an emphasis on being as lightweight as possible, especially for gaming or performance-sensitive scenarios. In contrast, input-remapper is in Python, and KMonad uses Haskell. Each has its own strengths, but Keyshift focuses specifically on runtime efficiency.
• Capabilities: Keyshift is more than a remapping tool—it’s designed to let users create layered key functions. For instance, you can set up configurations like CAPSLOCK+1 = F1 or DELETE+BACKSPACE = VOLUMEUP, making it easy to define combinations similar to a laptop’s Fn key functionality with added flexibility. I’m not sure if input-remapper offers something similar, but would be interested to hear more!
• GUI: input-remapper has a nice GUI, while Keyshift is config-driven. Here’s a quick example to give you a sense of how the config looks.

If input-remapper meets all your needs, there’s no reason to switch, though I’d still love any feedback if you decide to try Keyshift.

Feedback noted on the systemd example—I’ll include it. On installing a service in PKGBUILD, since it requires a keyboard device, I’ll need to rework it a bit—opened an issue here. Thanks again for the insights!