Tested some custom resources with a test scene.

scripts/EnemyResource.gd

@@ -0,0 +1,11 @@
+extends Resource
+class_name EnemyResource
+
+var primary_enemy_bullet: BulletResource = preload("res://scripts/BulletResource.gd")
+var exploding: bool
+
+@export var enemy_type: String
+@export var health: int
+@export var speed: int
+var start_pos: float 
+@export var tween_speed: float

scripts/EnemyResource.gd.uid

@@ -0,0 +1 @@
+uid://dxmlb4jyoucud

scripts/ExampleResource.gd

@@ -0,0 +1,7 @@
+extends Resource
+class_name ExampleResource
+
+@export var type: String = "Example"
+@export var speed: float = 10.0
+@export var sprite: Texture2D = preload("res://icon.svg")
+@export var new_type: bool = false

scripts/ExampleResource.gd.uid

@@ -0,0 +1 @@
+uid://0nsrno5ksdeh

scripts/bullet_stats.gd

@@ -0,0 +1,15 @@
+class_name BulletStats
+extends Resource
+
+@export var bullet_type: String
+@export var bullet: String
+
+@export var damage: int
+@export var speed: int 
+
+
+func _init(bullet_type:String = "normal", bullet:String = "res://resources/bullet_resource.tres", damage:int = 1, speed:int = 150):
+  self.bullet_type = bullet_type
+  self.bullet = bullet
+  self.damage = damage
+  self.speed = speed

scripts/bullet_stats.gd.uid

@@ -0,0 +1 @@
+uid://64l0xhnsdh7x