I tried to install again, on a 64GB USB3 mSATA, this time I modified the install options, swapsize=8, minfree=0, maxvz=0, and
maxroot=48, the result is a 14.8GB root volume.
root@server-1:~# lsblk
...
sdr 65:16 0 59.6G 0 disk
├─sdr1 65:17 0 1007K 0 part
├─sdr2...