I think it depends on the specific trial design if we should limit the number of NACT cycles or not:

If the trial intervention starts right after IDS more or less cycles of NACT most likely make a difference.

If the trial intervention starts after completion of first line chemotherapy (e.g. Pure maintenance trial) I believe it does not make much of a difference if we do IDS after 2,3,5,6 cycles or not at all, cause most first line trials also include patients that were inoperable from the beginning.