This tmux config turns F12 into a button to toggle the local leader key. You remote into tmux and hit F12, and now your leader key gets sent to the remote tmux instead of the local.

I don't use tmux locally anymore; but I still use the same leader key as tmux in wezterm, and I have a wezterm script to toggle it with F12 just like tmux.

Maybe you'll like it too?

  bind -T root F12  \
    set prefix None \;\
    set key-table off \;\
    set status-style "fg=$color_status_text,bg=$color_window_off_status_bg" \;\
    set window-status-current-style "fg=$color_dark,bold,bg=$color_window_off_status_current_bg" \;\
    if -F '#{pane_in_mode}' 'send-keys -X cancel' \;\
    refresh-client -S \;\

  bind -T off F12 \
    set -u prefix \;\
    set -u key-table \;\
    set -u status-style \;\
    set -u window-status-current-style \;\
    set -u window-status-current-format \;\
    refresh-client -S