Stop SKAction after a certain amount of time

I have a number of enemies that spawn at separate times in my game, and move using SKAction but at the end of each level I have a boss that spawns in. When the boss spawns I want the other enemies to stop spawning. I have a function for each enemy. I'm using the withKey: in my SKAction.sequence for each enemy and then use the removeAction(forKey: ) in the boss function to stop it but it doesn't work. Am I using this in a wrong way.

example of my code (only left in the SKAction code, removed all other code)

override func didMove(to view: SKView) {
       //Spawn Enemy1
        run(SKAction.repeatForever(
          SKAction.sequence([SKAction.run() { [weak self] in
                              self?.addEnemy1()
                            },
                            SKAction.wait(forDuration: 5.0)])))

}

func addEnemy1() {
        
        let delay = SKAction.wait(forDuration: 10)
        let actionMove = SKAction.moveTo(y: -600, duration: 5.0)
        let actionRemove = SKAction.removeFromParent()
        enemy1.run(SKAction.sequence([delay, actionMove, actionRemove]), withKey:"enemy1")
        
    }

func addBoss() {
        
        let move1 = SKAction.moveTo(y: size.height / 3.5, duration: 3)
        let move2 = SKAction.moveTo(x: size.width / 3, duration: 3)
        let move3 = SKAction.moveTo(x: 0 - boss.size.width, duration: 3)
        let move4 = SKAction.moveTo(x: 0, duration: 1.5)
        let move5 = SKAction.fadeOut(withDuration: 0.2)
        let move6 = SKAction.fadeIn(withDuration: 0.2)
        let move7 = SKAction.moveTo(y: 0 - boss.size.height * 3, duration: 3)
        let move8 = SKAction.moveTo(y: size.height / 3.5, duration: 3)

        let action = SKAction.repeat(SKAction.sequence([move5, move6]), count: 6)
        let repeatForever = SKAction.repeatForever(SKAction.sequence([move2, move3, move4, action, move7, move8]))
        let sequence = SKAction.sequence([move1, repeatForever])

        boss.run(sequence)
        
        enemy1.removeAction(forKey: "enemy1")
    }