Modular monoliths are hot! It combines the modularity of a microservices architecture with the ease of deployment of a monolith.
For a good introduction, have a look at the following video:
If you want to get started in .NET take a look at the following repository on Github: https://github.com/kgrzybek/modular-monolith-with-ddd
It contains a full modular monolith .NET (Core) application created using DDD and CQRS.