AFAIK there is a way to let lottie jump to markers. It is in their documentation somewhere, but I did not try it. But that GOTO command will never work, as this is not a valid AMCP command. You would need to do the coding in JavaScript and either use the NEXT command (inside your js code you can let Caspar call this) or using the INVOKE command with the name of a parameter less function in your js.
For hints about lottie and Caspar see this tread.