then it must be rare as hell because I can't find any even with spelunker or my underground snow got messed up because it's partially underground crimson snow
If you really want them and it isn't condtions (though, I believe they can spawn in the cavern layers too, not just the snow biome.), try a Zerg Potion, make sure you're in the right place.
Slimes for days.
(To get a Zerg potion, you'll need about...5/6 things. 1 bottle, 1 Deathweed, 2 murky sludge, 1 Vertebrae/Rotten Chunk, and 1 Demonic Bone ash. fill the bottle with water, make a Battle Potion using the newly made water bottle, Deathweed, and Vertebrae (Crimson)/Rotten Chunk (Corruption. Then using the newly made Battle potion (which increases spawn rates), craft the Zerg Potion using the Battle Potion, Demonic Bone Ash, and Murky Sludge. This,when used, will give you a buff called Zerg, which increases spawn rates by 30X, or about 3000%. The Buff lasts for 10 minutes and can be removed by right clicking it, just like any other buffs (Debuffs can't be removed.). This method of getting Zerg Potions requires and Alchemy table to use for the crafting station, atleast for the zerg potion part. The battle potion may be made at a bottle on a shelf, but I'd suggest making it at an alchemy table, as it may save you materials.)
(Another method is a post-Providence way, Blood Orb farming. It's unlocked post moon lord but isn't as effective until you can get Bloodflare stuff. You'll need 1 Water Bottle and 20 blood orbs to get. But by this time you wouldn't need Cryo ore. Crafted at the Ancient Manipulator.)
Blood Orbs-10% chance to drop during blood moons (after Moon Lord) from enemies. 50% when Bloodflare armor is equipped (Set Bonus)
Bottles-sand+furnace. Go near water (Above a platform will do) to craft a water bottle.
Deathweed-Near the evil parts of a world
Vertebrae/Rotten Chunk-Dropped by Crimson/Corruption enemies respectively
Murky Sludge-about 20% droprate from a few enemies, Mother Slime, Crimslime, or Corrupt Slimes
Demonic Bone Ash-Bone Serpents drop these.
Hopefully that'll help a little.