I am very glad of the architecture we use at my current company. This is a monolith, BUT with the capacity to be deployed as microservices if needed.

The code is structured in such a way that you only start the sub services you need. We have node that launch almost all services, some only a few.

If we need to scale just a particular part of the system we can easily just scale the same node but configuring it just for the sub services we need.