Main Thread Checker Error: Double to UILabel Fails Swift

I am collecting some data from an API that Im then running some calculations on. The numbers are stored as Doubles since i want the decimals. Calculations and all running smooth, getting correct printouts in the console, however I cannot seem to get it to update my UILabel. Im getting the following error in the console (it builds successfully btw):

Main Thread Checker: UI API called on a background thread: -[UILabel setText:]
PID: 69869, TID: 13575919, Thread name: (none), Queue name: NSOperationQueue 0x113e13690 (QOS: UNSPECIFIED), QoS: 0

Here is my code and my calculations. The values are updated through the API so they’re not just 0 when I do the calculations:

    @IBOutlet weak var renewableLabel: UILabel!
    
    var hydroValue : Double = 0
    var windValue : Double = 0
    
    var renewables : Double = 0
    var renewPercent : Double = 0

 func calcIndex(){
        
        renewables = windValue + hydroValue
        renewPercent = Double(round(10*((renewables / productionValue) * 100))/10)
        
        //print(productionValue)
        
        print("(renewPercent) %")
           
        updateLabel()
}

func updateLabel(){
        renewableLabel.text = ("(renewPercent)")
    }

I tried reformatting the Double as a String prior to sending it to the Label but still the samr error. If I do this above in a different project with just the Doubles the renewableLabel.text = ("(renewPercent)") works fine. Im not sure even if a UILable is the best choice here. Im happy to switch :).

func updateLabel(){
    DispatchQueue.main.async {
        self.renewableLabel.text = ("(self.renewPercent)")
    }
}