Dual Boot Ubuntu 20.04 boot menu not showing suddenly

Question

I have a problem where my GRUB menu does not appear and would boot directly into Windows directly. I have tried the solutions of editing the /etc/default/grub file but it do not seem to work.

This is my /etc/default/grub file:

GRUB_DEFAULT="Advanced options for Ubuntu>Ubuntu, with Linux 5.13.0-52-generic"
GRUB_TIMEOUT_STYLE="menu"
GRUB_TIMEOUT="10"
GRUB_DISTRIBUTOR="`lsb_release -i -s 2> /dev/null || echo Debian`"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

Ubuntu is not shown in the BIOS as well.