rasputin
Not 100% sure but I think this line(s)
Modules linked in: lz4hc lz4hc_compress zlib rk_vcodec lzo zram ip_tables x_table
only state which modules are loaded, not necessarily that these are related to the error.
You can compare with: lsmod
I see zram… Ahh the ARMbian zRam implementation was added by some recent update of their rootfs package… This caused issues in another case already, so please try the steps provided here: https://dietpi.com/forum/t/troubleshooting-help-how-to-identify-random-reboots-and-or-non-responsive-device/3270/1
Aside from that, dmesg does not report any voltage/power related errors, does not? In case try another power supply. But not after ruling out that indeed zRam is the issue 
.