I think this may be exactly what I've been looking for. I've been wanting a "Better C" type of language, but all the existing candidates fall down on some point like - too complicated (Rust/D/C++), no manual memory management (Go), etc. I've even made some half baked attempts at writing my own language.
It seems that the design goals of this language are exactly what I'm after. Going to have to give it a try later.
Zig might be a good fit for you. Nim also seems to answer all your requirements.
Nim doesn't meet all his requirements, it's garbage-collected. Complexity is hard to measure and rather subjective, but Nim in my opinion seems to be more complex than Zig.
I do not know enough of Zig to compare the complexity, and Nim is indeed not simple. To borrow from the zen of Python, it is complex but not complicated; and most of its complexity is of a kind you can almost entirely ignore until you need it, and when you need it, you're in trouble if your programming language doesn't provide it. e.g. operational transforms, macros, compile time execution. pragmas.