Expanding LUKS drive
First make sure that the drive is opened and mounted.
Run the commands
sudo cryptsetup resize [Drive]
sudo resize2fs /dev/mapper/[Drive]
To find out what [Drive] is supposed to be, examine the following commands output
sudo lsblk
In the following example it would be crypt-sdf
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
nvme0n1 259:1 0 20G 0 disk
├─nvme0n1p1 259:2 0 20G 0 part /
└─nvme0n1p128 259:3 0 1M 0 part
nvme1n1 259:0 0 50G 0 disk
└─crypt-sdf 253:0 0 30G 0 crypt /mnt/sda