The perks you can upgrade in CoD Cold War Zombies are just one area you need to improve that use up Aetherium Crystals. It is wise to spend them on different areas and spread your upgrades.
The best perks to upgrade in Call of Duty Cold War Zombies will be shown below and explained why they are powerful. There are some combinations of perks, skills, and weapons to watch out for as well because some are just overpowered compared to spreading them out evenly.
Perk Upgrade Priorities
While most of the perks have a good base effect, there are some that have incredibly overpowered upgraded tiers that can be prioritized to help you get to the higher rounds with a better weapon.
The Speed Cola perk is already good without the tiers but a faster reload time is extremely important when there are endless waves of zombies coming out in the later rounds. If you do not kill them fast enough, your team will get overrun and lose. The 30% reload speed is extremely fast and makes the LMG weapons useable in the late game.
The field upgrades are also excellent if you have one at max tier where it can be used more often. The tier 1 upgrade which increases your swap weapon speed is not a big deal since you do not switch weapons often enough to make use of it. It is only good if you get stuck with a bunch of zombies and need to swap weapons to make a path because your main weapon ran out of ammo.
Since you will only have one main weapon upgraded by the Pack-A-Punch machine, you will rarely swap to your lesser weapon when fighting. The Pack-A-Punch upgrade is expensive, and you will most likely be upgrading only one weapon unless you reach round 25 and above. You also want to be thrifty when purchasing anything that involves essences if you want to upgrade 2 weapons to max.
The Deadshot Daiquiri perk is good even without the right weapons. If you pair this with a tactical rifle or a shotgun, this perk will absolutely go berserk. Every single tier level is an insane upgrade for these kinds of weapons and combine it with the tier 3 Speed Cola, you will be hitting round 30 on a regular basis.
The armor penetration is almost required for fighting armored zombies in the late rounds. The Deadshot Daiquiri is often overlooked because it is placed in a usual spot. Once you go down to the bunker, turn right and open the door that can lead to the Pack-A-Punch machine. Before going to the center, you will see a missile and just jump down below it and find the Deadshot Daiquiri vending machine.
The Elemental Pop is also good for the endgame where you can have a random ammo mod apply along with your existing one. This is more powerful when you already have the capability of upgrading your weapon in the Pack-A-Punch machine which only costs around 2,000 essences.
It is only good at the mid to late game part because you will have to get the weapon you want first so you can be efficient with your essences. The tier 3 upgrade is extremely powerful because of how it mirrors your highest skill tier ammo mod to the effect of the Elemental Pop perk.
Jugger-Nog is more for survivability and you would not need a lot of that if you are already powerful enough to fend off zombies before getting to you. Easier said than done but it is also great to have a buffer for mistakes and this is why the Jugger-Nog is also quite important.
The armor plates are hard to repair and can easily break but you will find armor plates drop from zombies or from breaking crystals which is more common.
The Stamin-up and the Quick Revive perks are both okay but their tier upgrades are underwhelming. Their base effect is already good but these are the last perks you want to be upgraded just because the others are just extremely powerful when at tier 3. Sometimes, the aim walking speed is great for niche weapons but you would still want more firepower to get zombies off than just kiting and exhausting more ammo.
The tier 3 Quick Revive perk is also good in certain scenarios because reviving teammates in the late rounds is almost impossible and it will only be possible with this tier 3 upgrade. This scenario does not happen often and a good player will less likely be affected by this which makes this perk not a priority to be upgraded.
Most of these perks depend on a lot of things like skills, weapons, ammo mods so you should spread out your Aetherium Crystals on those upgrades as well and not focus everything on perks. While the top 3 perks are extremely useful at tier 3, it is still best to spread it on weapon upgrades like the shotgun tier 3, Deadshot Daiquiri tier 3, and Napalm Burst ammo mod tier 3.