No language runtime is ever in a state of "obviously no bugs".
Good luck demanding that of anything of JSC's or LLVM's complexity
My Elm code base was virtually bug free. My current python code base is riddled with small bugs. Some designs makes it easy to trust your code. Some make it die by a thousand paper cuts.
Big llm rewrites I fear lead to the latter.
Perhaps then it would be better to not use tools of this level of complexity.
On one hand, sure, the entire point of a programming language is to make complex ideas able to be expressed in simpler abstractions. On the other hand, we can damn well try.