Hello Pimvdmeer,
Might be able to add some pause/wait in between (change 0.5 to however many seconds you need):
/itemrack equipset (setname)
/click pause 0.5
/use 14
/click pause 0.5
/itemrack equipset (setname)
A bit more explanation with example here: GSE Pause / Wait: Stop Wasting Multi Charges Abilities