Simplified millis calculation

src/main/java/net/minestom/server/entity/Entity.java

@@ -1536,7 +1536,7 @@ public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, Da
             this.scheduledRemoveTime = 0;
             return;
         }
-        this.scheduledRemoveTime = System.currentTimeMillis() + temporalUnit.getDuration().multipliedBy(delay).toMillis();
+        this.scheduledRemoveTime = System.currentTimeMillis() + TimeUnit.getMillis(delay, temporalUnit);
     }
 
     /**

src/main/java/net/minestom/server/entity/ItemEntity.java

@@ -242,7 +242,7 @@ public class ItemEntity extends Entity {
      * @param temporalUnit the unit of the delay
      */
     public void setPickupDelay(long delay, @NotNull TemporalUnit temporalUnit) {
-        this.pickupDelay = temporalUnit.getDuration().multipliedBy(delay).toMillis();
+        this.pickupDelay = TimeUnit.getMillis(delay, temporalUnit);
     }
 
     /**

src/main/java/net/minestom/server/entity/LivingEntity.java

@@ -670,10 +670,10 @@ public class LivingEntity extends Entity implements EquipmentHandler {
      * Changes the delay between two fire damage applications.
      *
      * @param fireDamagePeriod the delay
-     * @param temporalUnit         the time unit
+     * @param temporalUnit     the time unit
      */
     public void setFireDamagePeriod(long fireDamagePeriod, @NotNull TemporalUnit temporalUnit) {
-        fireDamagePeriod = temporalUnit.getDuration().multipliedBy(fireDamagePeriod).toMillis();
+        fireDamagePeriod = TimeUnit.getMillis(fireDamagePeriod, temporalUnit);
         this.fireDamagePeriod = fireDamagePeriod;
     }
 

src/main/java/net/minestom/server/utils/time/UpdateOption.java

@@ -48,7 +48,7 @@ public class UpdateOption {
      * @return the converted milliseconds based on the time value and the unit
      */
     public long toMilliseconds() {
-        return temporalUnit.getDuration().multipliedBy(value).toMillis();
+        return TimeUnit.getMillis(value, temporalUnit);
     }
 
     public Duration toDuration() {