Uninstall Endless (I want to change it to Windows 10 PRO)

I don’t believe you can write the Windows ISO to a USB stick and boot it, actually. (Unlike Endless OS and other Linux distro ISOs which are “hybrid” images.)

Microsoft provides a tool for Windows that writes ISOs to USB sticks. If you have a UEFI system you could also probably just format the USB stick as FAT32 and copy the entire contents of the ISO onto the USB stick.