You are going to need to run a rescue system to get this sorted, for example from an USB stick. Usually you can enter UEFI setup by just spamming the button on boot (F2, F12, F10, Del, look up what your system uses). If that doesn’t work you can either reset the BIOS settings, using the jumper or button (see manual again, removing the battery is internet lore and almost never required, just use the jumper). Another option is to remove your boot drive, that will prevent fastboot from working, so the next boot will be a regular one.