Order events are available in Marketplace Webhooks

Developers can now subscribe to OrderCreate and OrderStatusUpdate in the marketplace for their custom app development.

This is available as OrderCreate & OrderStatusUpdate in app settings with payments/orders.readonly scope configurable at location level (Screenshot attached for reference)

OrderCreate - This occurs whenever an order is created.

OrderStatusUpdate - This occurs whenever an order status is changed. Possible order status are pending, completed, or cancelled