Cannot access Ubuntu 18.04 in dual boot, because system boots straight to Windows 10

I have tried several method from previous answers:

1. Changing boot order from BIOS menu. There is no option of Ubuntu in BIOS.


2. Repairing grub menu after loading Ubuntu from USB.


3. Changing boot order from efibootmgr Ubuntu.


4. Using command like bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi or
   bcdedit /set {bootmgr} path \EFI\Microsoft\Boot\bootmgfw.efi in cmd.

Fast startup is disabled.