Seeing as F10 works to get you the list of boot options, could you try that again and see if there's an option in the list to enter BIOS / UEFI? I have seen this on several different systems.
If not, try installing another USB stick with Ventoy and then copy your Windows ISO on it - do not burn the Windows ISO, just copy it across like any other file. If you can boot into that stick from the F10 list, you can either go straight into the Windows installer, or otherwise you can hit one of the F-keys (I forgot which, I think F4 or F5) at the Ventoy screen to get a list of other options which includes rebooting into BIOS / UEFI.
Also, this has caught me out before, but are you trying to use a 64bit Windows ISO? It could be the laptop only supports booting in 32bit (even if the CPU is 64bit!)
Finally, there should be a way to make grub display even if there's only one linux OS installed, and the grub menu should have a BIOS / UEFI options. Spam / hold either the Shift or Esc keys, depending on if you have BIOS or UEFI.