I don't know...

src/main/resources/data/minions/recipe/basic_upgrade.json

@@ -6,15 +6,9 @@
     "RGR"
   ],
   "key": {
-    "R": {
-      "item":"minecraft:redstone_block"
-    },
-    "G": {
-      "item": "minecraft:gold_ingot"
-    },
-    "D": {
-      "item": "minecraft:diamond_block"
-    }
+    "R": "minecraft:redstone_block",
+    "G": "minecraft:gold_ingot",
+    "D": "minecraft:diamond_block"
   },
   "result": {
     "id": "minions:basic_upgrade_base",

src/main/resources/data/minions/recipe/minion.json

@@ -6,18 +6,10 @@
     " L "
   ],
   "key": {
-    "H": {
-      "tag": "minecraft:skulls"
-    },
-    "R": {
-      "item": "minecraft:redstone_torch"
-    },
-    "A": {
-      "item": "minecraft:armor_stand"
-    },
-    "L": {
-      "item":"minecraft:lodestone"
-    }
+    "H": "#minecraft:skulls",
+    "R": "minecraft:redstone_torch",
+    "A": "minecraft:armor_stand",
+    "L": "minecraft:lodestone"
   },
   "result": {
     "id": "minions:minion",

src/main/resources/data/minions/recipe/mount_upgrade.json

@@ -1,14 +1,8 @@
 {
   "type": "minecraft:smithing_transform",
-  "base": {
-    "item": "minions:basic_upgrade_base"
-  },
-  "addition": {
-    "item": "minecraft:minecart"
-  },
-  "template": {
-    "item": "minecraft:netherite_upgrade_smithing_template"
-  },
+  "base": "minions:basic_upgrade_base",
+  "addition": "minecraft:minecart",
+  "template": "minecraft:netherite_upgrade_smithing_template",
   "result": {
     "id": "minions:mount_module"
   }

src/main/resources/data/minions/recipe/move_upgrade.json

@@ -1,14 +1,8 @@
 {
   "type": "minecraft:smithing_transform",
-  "base": {
-    "item": "minions:basic_upgrade_base"
-  },
-  "addition": {
-    "item": "minecraft:iron_boots"
-  },
-  "template": {
-    "item": "minecraft:netherite_upgrade_smithing_template"
-  },
+  "base": "minions:basic_upgrade_base",
+  "addition": "minecraft:iron_boots",
+  "template": "minecraft:netherite_upgrade_smithing_template",
   "result": {
     "id": "minions:move_module"
   }