the bar end shifter , particularly the friction/power ratchet ones
are exceptionally reliable.. mine are 30 years old, still work fine..
before that I had down tube mounted levers,
a quick slap made 1 gear downshift, on the RD,
to limit time not holding on the bars, with both hands.


I went from bar end shifted derailleur bikes to the 14 speed Rohloff IGH.

which uses a pull-pull 2 cable shifting grip... in event, should a cable break
the hub can be shifted with an 8mm wrench, on the hub
as the whole sequencing mech, is in the hub.

grip shifter and trekking /figure 8 bars is a nice combination
being the right diameter match.