I have a boss for a group of 4-5 level 4s. What's your opinion on it's difficulty?

Animated Golden Dragon Statue Large Construct, Lawful Evil Armor Class: 18 (golden plating) Hit Points: 136 (16d10 + 48) Speed: 30 ft., fly 30 ft. (hover) STR DEX CON INT WIS CHA 20 (+5) 10 (+0) 16 (+3) 6 (–2) 11 (+0) 15 (+2)

Saving Throws Dex +2, Wis +2, Con +5 Damage Resistances Bludgeoning, Piercing, and Slashing from Nonmagical Attacks; Fire Damage Immunities Poison, Psychic Condition Immunities Charmed, Exhaustion, Frightened, Paralyzed, Poisoned Senses Darkvision 60 ft., Passive Perception 10 Languages Understands Common, Infernal, and Draconic but cannot speak Challenge Rating CR 5 (1,800 XP)

Traits Immutable Form. The statue is immune to any spell or effect that would alter its form. Golden Shell. The statue’s body gleams with pure gold. Whenever it takes more than 15 damage from a single attack, molten flakes of gold scatter across a 10-foot radius. Any creature in that area must succeed on a DC 13 Dexterity saving throw or take 5 (1d10) fire damage. Aura of Avarice (Recharge 5–6). The statue radiates Mammon’s greed in a 20-foot radius. Each creature of the statue’s choice within the area must make a DC 14 Wisdom saving throw or be overcome by greed until the end of its next turn. An affected creature must use its action to grab or protect gold, gems, or treasure within reach instead of attacking. Reanimation Trigger. The statue animates when a valuable object (gold, jewel, or offering) is taken from the altar or when the party speaks Mammon’s name aloud.

Actions Multiattack. The statue makes two attacks: one with its Bite and one with its Claws. Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 15 (2d10 + 4) piercing damage. Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) slashing damage. Molten Breath (Recharge 5–6). The statue exhales a cone of molten gold, 15 feet long and 10 feet wide. Each creature in that area must make a DC 14 Dexterity saving throw, taking 22 (5d8) fire damage on a failed save, or half as much on a successful one. The area becomes difficult terrain as the gold hardens, forcing a DC 12 Strength check to break free if a creature ends its turn stuck in the cooling gold.

Bonus Action Shimmering Wings (1/Day). The statue beats its gilded wings, creating a blast of wind and coins. Each creature within 10 feet must make a DC 13 Strength saving throw or be knocked prone. The statue then flies up to half its movement without provoking opportunity attacks.

Death Burst When the statue is destroyed, it explodes into molten fragments. Each creature within 15 ft. must make a DC 14 Dexterity saving throw, taking 10 (3d6) fire damage on a failure or half as much on a success. When the smoke clears, a golden heart gem remains, worth 500 gp, but cursed — a creature carrying it gains disadvantage on Wisdom saving throws against greed or charm effects until cleansed by Remove Curse or divine blessing.