It's difficult to say, if you have any spares of that, like a different PSU start with what you can test and rule out, you can also try with just two DIMMs at one time, to completely rule out the RAM.
I'm really not a network guy, but always read you need different subnets for that, you can also add the server name with the 10GbE IP to the hosts file on the client computer, so you can access it by name still using 10GbE, that's what I do.
If the disk was empty might as well reformat, but you can try to mount it with UD plugin and if it doesn't post the diags (key needs to be the same as other encrypted disks in the server).
Does is still reboot frequently with the RAM running @ 2133 MT/s? If yes one thing you can try it to boot the server in safe mode with all docker/VMs disable, let it run as a basic NAS for a while, if it still crashes it's likely a hardware problem, if it doesn't start turning on the other services one by one.
No valid filesystem is being detected, so there's serious damage to the superblock which may make recovery difficult, all your other disks are empty, was that the only disk with data?
RAM is running at 3600MT/s, max supported speed for you CPU with 4 dual rank DIMMs is 2667 MT/s, in any case this is general support issue, so please continue discussion here:
reiserfsck --rebuild-sb /dev/sde1
Follow the instructions carefully, once it's done:
reiserfsck --rebuild-tree /dev/sde1
This last one will take several hours.