[2022] EndgameCraftCost ?

You need to add the EndgameCraftCost variable to your Difficulty.eco:
{ "CollaborationPreset": "MediumCollaboration", "DifficultyModifiers": { "SpecialtyCostMultiplier": 1.0, "SkillGainMultiplier": 1.0, "SpecialtyExperiencePerLevel": 25.0, "CraftResourceModifier": 1.0, "CraftTimeModifier": 1.0, "PlayerExperiencePerSpecialtyExperience": 0.0 }, "EndgameCraftCost": "Expensive" }

When it works the recipes will be different and hence shown different in the tooltips as well, yes :)

Yes, that's the changed recipe. It can be set back to 'Normal' at any time, only a Computer Lab that is already set up for crafting won't retroactively change your recipe. If it doesn't change recipe for you after changing the variable, there is some issue with your server not taking the values out of it.

No, the recipe only affects the Computer Lab, as lended from White-Tiger back then.