I think that you can wire a function rather than a var as the result of `fetchL2PropertyValues`.

This means it's basically a callback where you can set values and run your other logic.

So you'd write it like:


    @wire(fetchL2ProductValues,{productId: '$l1SavedValue',userType: '$userType'})
    l2ProductValuesCallback({ error, data }) {
        if (data) {
           this.l2ProductList = data;
            //do all the logic you wanted to run in the callback... 
           var key,count =0;
           for(key in this.l2ProductList){
             if(this.l2ProductList.hasOwnProperty(key)){
               count++;
             }
           }
           if(count > 0){
               this.showProductL2 = true;
           }else{
               this.showProductL2 = false;
           }
        
        } else if (error) {
            //handle your error
        }
    }

Also... that logic seems like it could be simplified - try investigating `array.some()` which iterates until a condition evaluates to true. Depends on the data structure of your list that you are returning.