Schaller: What to look for in Fedora Workstation 34

That isn't true. The libxkbcommon code will pick up configuration files under $HOME/.config/xkb, $HOME/.xkb, /etc/xkb, or other paths that you can define with environment variables[1]. There are also environment variables for the default rules, model, layout, variant, and options[2]. As long as the Wayland compositor follows recommended best practices and doesn't try to override the default settings you should be able to use whatever XKB configuration you prefer, including ones not present in the system directories. You just need to restart the compositor to apply any changes, unless the compositor (like X11) happens to implement a protocol to modify the XKB context.

[1] https://xkbcommon.org/doc/current/group__include-path.html
[2] https://xkbcommon.org/doc/current/group__context.html