The list was created by Arlek Theory#3333 from the Official Global Discord and all credits goes to him.
Shops and currencies
With Admin Coins (the Premium Currency), buy the Battlepass only as a low spender. If you're a dolphin, buy the Golden Binaries packs as that's the rarest currency in game (gear is the real gacha in Counter Side).
With Quartz, buy the weekly Classified Recruitment Package for 2750, Gold Bins Monthly Pack for 1000. Remaining Quartz can be spent on daily shop resets.
With Task Planet Points, buy Operators. Preferably Kim Hana if PvE focused or Sigma if PvP focused. Later you will also buy Unit Data for characters that received Rearms to upgrade their skills.
With Credits, buy all items that can be bought with Gold on "Todays Deal". Refresh the shop 5 times with Quartz - it's worth it. Don't waste your Credits on leveling characters - just do it slowly over time as you farm/skip stages.
With Gauntlet points, the first priority are the 80 Classified Recruitment tickets. Next priority is Maze and Gordias Gears. Preferably Counter Maze then Gordias Crown then Gordias Movement.
With Dive Imaginary Cores, buy the Special Ship Schematics first, then the Unique Materials for a ship you're currently building/upgrading.
With Ownerless Business Cards, buy the limited items weekly.
With Partner Business Cards, well, pull for N and R rarity, then sell them for Ownerless Business Cards then see above.
With Danger Close Performance Points, buy the Maze and Hummingbird Gears.
With Challenge Medals, buy the Maze Gears.
With Consortium Tokens, purchase the Gold Binaries then the Fusion Cores then the APT cores.
With Event currency, clear the entire shop besides the gear. Gear pieces from events aren't usually worth it.