I thought that maybe developer mode might have to do something with it so I tried powerwash and then network recovery. It is supposed to repartition the hard drive and fix any issues. But I still get the same result.
Why the system is taking 60 GB out of the box? Isn’t it supposed to be around 16GB?
lsblk shows you the size of “devices” and not how much space they take.
Based on your screenshot, Chrome OS take ~8GiB on your device. The first partition (nvme0n1p1) is actually the user data partition. This link should give you an overview of Chrome OS’ partitions design.
Within the user data partition, it seems that they uses LVM+dm-crypt to divide and encrypt the home area of individual users, evident by this (potentially out-of-date) documentation: ChromiumOS Platform - Filesystem layout