Yes, you can, but please be aware that Across is actually better suited for developing modular monoliths and does not necessarily bring much added value for small applications often representing a single module.
The Spring Boot and Spring Cloud communities are very active when it comes to microservices and most of their features have not yet been tested in Across based applications. It might involve some more in-depth technical work to get things working correctly. We can offer commercial support for this if required.
In future releases of Across we expect to improve the out-of-the-box integration with Spring Boot and Spring Cloud libraries.