I wonder if anyone has tried this thing before, like... micro-projects or such... ;)

Splitting one big codebase into 100 microservices always seems tempting, except that big codebases already exist in modules and that doesn't stop one module's concerns from polluting the other modules' code. What you've got now is 100 different repositories that all depend on each other, get deployed separately, and can only be tested with some awful docker-compose setup. Frankly, given the impedance of hopping back and forth between repos separated by APIs, I'd expect an LLM to do far worse in a microservice ecosystem than in an equivalent monolith.

It's not the size that's the issue, it's the domain that is. It's tempting to say that adding drivers to Linux is hard because Linux is big, but that's not the issue.