Bug
If the plugin was installed anywhere other than in ~/.tmux/plugins/tmux-wormhole/, the bash script can't find the executable (source).
Context
The plugin assumes that it will be installed in ~/.tmux/plugins/. But since version 3.1, tmux config files can alternatively be stored in ~/.config/tmux/, and since 3.2, in $XDG_CONFIG_HOME/tmux/. Also, TPM can override the location of plugins.
Proposed solution
Look for the executable in all the possible locations:
${TMUX_PLUGIN_MANAGER_PATH}/tmux-wormhole/tmux-wormhole
${XDG_CONFIG_HOME}/tmux/plugins/tmux-wormhole/tmux-wormhole
~/.config/tmux/plugins/tmux-wormhole/tmux-wormhole
~/.tmux/plugins/tmux-wormhole/tmux-wormhole