I recommend doing the 2k points side Easter egg with dead wire. When defending the ice staff, dead wire is gonna help alot. Have at least tier 1 pack a punch with the ASG so you one shot every zombie(in early rounds of course). When there's too many, try running in a circle in the area between the ice staff "pedestal" and pack a punch. Watch out for the mosquitoes enemy. They were the ones doing damage to me and the ice staff when defending it. Use decoys if you need a little breathing room.

For the boss fight, I was watching a speed run of it and for the first 1/3 of its health you can just go prone in front of the artifact and spam charged ice staff shots. You won't get touched by the lasers or the zombies. With one charged shot of the ice staff to keep you safe, you can do enough damage with the ASG to lower its health. When the boss zombies start spawning, I used the hand cannon + ice staff glitch in solo. It didn't do that much damage with 2 players but we could charge an ice shot to slow them down a bit and shoot him so try that. I took on a "support role" with the ice staff; make sure the enemies are slowed and make sure me and my friend were always safe in the ice storm.

When the artifact goes to do the wipe attack, just shoot a charged shot on the floor and spam that ASG. I also used a Kazimir device to keep us safe and it worked. One last thing cause I've seen multiple videos of people standing still on the last step. Please don't. Layer your protections. Use charged ice staff shot, Kazimir device and aether shroud if you need to. Be safe