The warzone bot lobby event may include specific challenges which give additional XP. Completing Listkeeper itself could give you an impressive amount of experience and a Dark Ops call card. Each camo unlock provides XP. If you follow this guide, do the Easter-egg steps and use the free-fire-trick you'll be passively gaining level. One operative reported that Endurance ("Endgame") is a great way to gain XP.
You can summarize the best BO7 holiday XP farming by looking at the combination of akimbo shots + free fire glitch, plus double XP. This is basically a free way to reach the maximum level as you enjoy snow. But don't forget to enjoy the actual event - while blasting with no challenge can be fun, you still have to earn your camo, soldier!
BO7 Zombies Guide for Christmas
The final thing to note is that this event has some bugs.
Low Present Drop rate (Boss Fighter Frustration). This makes the fight difficult for solo players, in particular. Our own experience and the experiences of many players suggest that "every two or three zombies drop a little present" rather than the sparse drops currently. Treyarch can adjust this via a new patch. For now, expect to grind. It might take a lot of tries to achieve the perfect strategy or many attempts if your goal is to go it alone. So don't be ashamed if friends are needed to help. Infestation's camo is rare and difficult to obtain.
Field Upgrade Glitch. Some have reported that, occasionally, equipment or field upgrades do not activate (e.g. Power Keg gobblegum/consumables fail to pop. One operative complained about his Power Keg not deploying during the boss. It could have been a problem. If you want to mitigate the problem, don't spam activate. Just tap it once for a half second. Make sure you have your consumables on. You should always have a fallback plan in place. For example, if the invincibility gobblegum breaks, you may want to use Aether Shroud or run.
Quick Revive/AutoRevive Issue - It appears that self-revive is not working properly in this mode. "No... this stupid freaking enhance doesn't work." We fixed that two updates ago but it's now [broken again] - this indicates an auto-revive was not triggered. Do not rely on your perk in solo. Instead, keep a Self-Revive manual handy. In coop, if the revive of your teammate does not work, reach out to them, and revive manually, instead of assuming that they'll wake up.
Elemental Pop & Randomkills: As we mentioned earlier, Pack-a Punch and Elemental Pop effects may sabotage a challenge that requires precision. One player noted that the PAP effect on a gun made the precision challenge "way harder" as it would keep popping and killing his entire horde. If you're using a weapon which has a bad effect (i.e. Brain Rot turns zombies), then it may be worth swapping the gun or repacking to get a better result. To get a better effect, you can swap out the gun for another one or change its packing before attempting a challenging challenge that involves controlled killing. You can use another mmoset gun to complete the challenge if you don't want to shoot the weapon which has the effect.
"Oscar", as well as other elements that are not visible: In the transcripts, it is mentioned that Oscar was not part of the Listkeeper's challenge. Oscar might be the mini-boss on the normal version or even a side quest. Listkeeper event mode skips over some of the normal quest elements. You shouldn't be concerned if normal map events like the appearance of an intermediate named Oscar or another boss don't appear - it's part of this mode. You can also use the beefed up weapons if an unexpected boss appears mid-challenge. It might be a side effect of playing in an event.
Co-Op: Make sure you give everyone credit when unlocking camouflage. When one person successfully completes an objective for a group Easter egg, everyone gets the reward. For example, Mutilate came unlocked after the Outdoor Challenge was completed. After completing the challenge, check your camo selection to make sure that all camos are unlocked. In that case, you may have to accomplish certain tasks individually (though, according to our intelligence, the camo was unlocked when everyone worked together). Working together is important - the holiday season is a time to give.
Extraction: If it is possible, make sure you use it when you're in a secure environment. It's important to remember that the exfil option may not even be available when facing a final challenge/boss. The best thing to do is finish it. Otherwise, you will lose progress. If you pass out, you'll have to redo everything. So, try to live or always have an auto-revive on hand.
You've completed a full-blown Zombies Easter Egg under extreme conditions. You've achieved a full-blown Zombies Easter Egg - under extreme circumstances - and gained several unique camos on the way. Infestation is the ultimate symbol of victory over zombies.
Conclusion
You started by lighting the fires and ended up extinguishing what was the biggest winter threat. This is more than camo. This is a badge. It's a tough mission, as our veteran says: "I went into this knowing that I might die... But let me know if someone has completed it solo." You won, solo or with your squad. Use your Infestation-camo with pride. It tells everyone that you have beaten BO7's Zombies for Christmas event.
Now that you've completed your mission, it's time for some fun. Enjoy your holiday carnage.