Just adjust it if you actually need the RAM and it isn’t relinquishing quickly enough.

options zfs zfs_arc_max=17179869184 in /etc/modprobe.d/zfs.conf, update-initramfs -u, reboot - this will limit ZFS ARC to 16GiB.

arc_summary to see what it’s using now.

As for using a simple fs on LVM, do you not care about data integrity?

relatable

So will I.

Religion is fucking bad, though: without hyperbole, it is and always has been a scourge on our collective existence.