We've done the round trip of splitting up a monolith into microservices and then going back the other way. Network API overhead being the biggest reason. This kind of hell is totally unnecessary until it absolutely is (i.e. hard information theory requirements demand you spread your app across more than 1 physical computer).

Monolith is better in almost every way. The only thing that still bothers us is the build/iteration time. We could resolve this by breaking our gigantic dll into smaller ones that can be built more incrementally. This is on my list for 2023.