PC Recycler

boot from usb with ubuntu boot repair, follow the instructions to unencrypt the drive. mount it then chroot into it. then start the boot repair tool.

https://www.shadowinfosec.io/2017/07/mounting-encrypted-hard-disk-luks-using.html

  Install the necessary requisite tools
      apt-get install lvm2 cryptsetup
  Create directory to mount the drive to
      mkdir /media/test
  Load the dm-crypt kernel module
      modprobe dm-crypt
  Open the partition using cryptsetup and enter the encryption password
      cryptsetup luksOpen /dev/sda3 test
  Activate all volume groups available
      vgchange -ay
  Mount the partition to the directory created earlier
      mount /dev/ubuntu-vg/root /media/test
  Access the hard drive on the mounted location
      cd /media/test