I think that depends on the size of the project. If it's a single piece of software that runs on one or a few machines, sure. But the OP talks about complex,

I think that depends on the size of the project. If it's a single piece of software that runs on one or a few machines, sure. But the OP talks about complex, distributed systems that run on several different hardware architectures, and probably implemented by several dozens or maybe hundreds of software engineers. I think you really need an architect for some key decisions: where does what kind of data come from, where is the source of truth for which data, what protocols are used for communication between them etc. Maybe that's more of a system architect than a software architect, but the lines are kinda blurry.