Strictly, jack does not detect card itself, but offers the option of using one or the other. If you do not see your zoom r16 named in qjackctl (small arrow to drop down to the right of the interface), two things can happen:
1) You really, the card has not been detected by Linux (which would be the "driver" or "module" ALSA, ALSA being critical audio system Linux). That is determined by the command I gave you before.
2) That itself is detected but qjackctl not recognize by name, but only by their alphanumeric identification "hw: x", where x is a number: 0, 1, 2 ...
Which answers the terminal when you enter this command? (you can copy and paste with the mouse, do not use Ctrl-C / V in the terminal)
There would be a third case, which itself is detected but is not supported 100%. But that would be seen later, have to do some research in that case.