Where is all my VM disk space at?

So I’m noticing space is getting rather tight on the Jellyfin server’s space (the server, not the media space):

This is running on Docker in a Ubuntu Server VM.

Checking space usage on the system…

ncdu 1.19 ~ Use the arrow keys to navigate, press ? for help
--- / ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
   60.8 GiB [############################] /usr
   16.3 GiB [#######                     ] /var
.   8.9 GiB [####                        ] /mnt
    2.0 GiB [                            ]  swap.img
  203.2 MiB [                            ] /boot
    6.6 MiB [                            ] /etc
    2.2 MiB [                            ] /run
  356.0 KiB [                            ] /opt
  188.0 KiB [                            ] /home
   80.0 KiB [                            ] /tmp
   44.0 KiB [                            ] /root
   24.0 KiB [                            ] /path
e  16.0 KiB [                            ] /lost+found
    8.0 KiB [                            ] /snap
e   4.0 KiB [                            ] /srv
e   4.0 KiB [                            ] /sbin.usr-is-merged
e   4.0 KiB [                            ] /media
e   4.0 KiB [                            ] /lib.usr-is-merged
e   4.0 KiB [                            ] /cdrom
e   4.0 KiB [                            ] /bin.usr-is-merged
.   0.0   B [                            ] /proc
    0.0   B [                            ] /sys
    0.0   B [                            ] /dev
@   0.0   B [                            ]  lib64
@   0.0   B [                            ]  sbin
@   0.0   B [                            ]  lib
@   0.0   B [                            ]  bin

*Total disk usage:  88.2 GiB   Apparent size: 128.1 TiB   Items: 1552022

This disbursement makes sense. I have apps making directories in usr/local to store their stuff, so it’s not spread out here and there in the system. Most of this usage is the Jellyfin server’s metadata. Meanwhile:

root@mittsume[~]# zfs get volsize jails/docker_prod-6liukk
NAME                      PROPERTY  VALUE    SOURCE
jails/docker_prod-6liukk  volsize   200G     local

I don’t understand how I can be using 88.2 GB and have less than 16 GB of space left on a 200 GB disk.