I can't tell if my project is a monolith or microservices, but it's going well so far. We use a single scalable database instance as a message broker and persistence source, and have a common framework implements distributed algorithms that every service uses to expose "OS-like" constructs (actor activation, persistent collections, workflows, Git etc. All communication is done through independent protocols.. there's not much coupling between protocols (except for common ones like "schedule this job on this device"), so it's not really a cobweb of dependencies, but everything relies on that single database.

I think if the database gets too overloaded I'll partition certain tree nodes across multiple masters (this is feasible because the framework doesn't rely on a single timestream).

With the level of shared code (the framework) and the single database, it's somewhat monolithic but the actors themselves are quite well-behaved and independent on top of it.