I am a person who uses Hello Fresh for realsies because it is a bit cheaper than groceries here and definitely cheaper than takeout, but we also remake the recipes when we want a specific one and don't want to wait for it to come around in the rotation again, and therefore I know The Secret Translations of Proprietary Ingredients:
"Cream sauce base" = make a roux, add milk according to how much cream sauce base you're supposed to have (ex: 4 oz cream sauce base = 4 oz milk)
"1 packet stock concentrate" = either one tablespoon Better than Bullion or, if you want to be really accurate, Savory Choice Broth Concentrate packets are available on Amazon and allegedly that's what they use
"Italian Heat Spice"/"Blackening Spice"/"Fry Seasoning"/etc.: I promise you someone on Reddit has figured out what spices they use and in what proportions for each mix, if it's not just a straight up branded mix (like McCormick Grill Mates Brown Sugar Bourbon spice mix)
"Roasted Garlic Herb Butter" (and other compound butters, like truffle butter) = they're literally Epicurean branded butters, they do not hide this, you can buy them online
"Sweet Soy Glaze"/"Ponzu sauce"/"Hoisin sauce" = literally Kikkoman brand condiments: they don't hide that, either
"Sweet Thai chili sauce" = any sweet Thai chili sauce from the grocery store will do. We use Blue Dragon or Taste of Thai because that's what we can get in our grocery store.