RtoL swipe is unutilized but still kind of feels weird for me (given that i am right handed and swipe LtoR for the remorse timer for example). Another idea could be to have a separate “close tab” mode activated with a long tap. And then use whatever swipe gesture.
Also:
One more suggestion for the open tab pulley (if possible technically). Since the bottom part (where the buttons reside in your patch) is stationary -meanin doesn’t move with the tab scroll- and is an easy reach point is it possible to add a pulley there and be activated only if you pull the bar upwards? Kind of similar to the way the media player shows the shuffle repeat etc buttons.