Hi there,
Yes, the cooktop will still work without power, but not the oven.
Please see page 17 of the user manual for steps on how to turn on the burner/s manually.
https://downloadcenter.samsung.com/content/UM/202502/20250214150059236/O_01._DG68-01339A-08_NX60A6511SS_AA_EN.pdf
^Rodel