Activate Tuner with trs footswitch

Really want the option to connect a TRS Footswitch to turn the tuner on and off.
Would much prefer this over holding the tuner button on the quad cortex.

Yes - just remember that NDSP introduced a new feature in 2.3.0 update, where you can swap Tuner/Tap Tempo activation mode (double tap for Tuner and Long Press for Tap Tempo).