This is based on the assumption that the purpose of microservices is to split up code. And that isn't a good reason to use microservcies, because it is possible

This is based on the assumption that the purpose of microservices is to split up code. And that isn't a good reason to use microservcies, because it is possible to modularize code and still combine in into a monolith. But for me the purpose of microservices is to isolate different pieces of functionality in order to increase stability. Microservices allow you to scale the resources available to each service independently and allocate the appropriate resource for each service, deploy changes to individual services at a time, rather than changing the entire application at once, have different SLAs for different services, and if done right can gracefully handle failure modes in one service without taking down the whole application.