If your system that used to dual-boot fine, one day just boots into Windows, with Linux nowhere to be found, you just need to add the Linux entry into the EFI boot manager.. No need to grub2-install, etc.
First find out which is the partition for linux with: fdisk -l /dev/sda
Then issue something like this from a rescue disk/flash drive..
Hint: -p is for partition number. Use the number you found above:
# efibootmgr -c -d /dev/sda -g -p 2 -L “centos” -l ‘\EFI\centos\shim.efi’
or, for Fedora:
# efibootmgr -c -d /dev/sda -p 2 -L “fedora” -l ‘\EFI\fedora\grubx64.efi’