ok so this should be the way to go

scenes/damage/CDamageable.cs

@@ -5,18 +5,18 @@ using Movementtests.interfaces;
 [GlobalClass]
 public partial class CDamageable : Node, IDamageable
 {
-    [Signal]
-    public delegate void DamageTakenEventHandler(float damageTaken);
+    public event Action<IDamageable, float> DamageTaken;
     
     [Export]
     public RDamageModifier[] DamageModifiers { get; set; }
 
+
     public float TakeDamage(RDamage damage)
     {
         var finalDamage = 0f;
         foreach (var damageable in DamageModifiers.ToIDamageables())
             finalDamage += damageable.TakeDamage(damage);
-        EmitSignalDamageTaken(finalDamage);
+        DamageTaken?.Invoke(this, finalDamage);
         return finalDamage;
     }
 }