Zed us, in fact, fully native. It's top-to-bottom Rust, which gives them C++ equivalent speeds or better compiles to native code and lets them much more easily make use of multi-threading parallelism than basically any other language that compiles to a static binary. They also use a custom GUI framework built from the graphics driver's up to be maximally efficient, performance smooth and low latency; that's literally the subject of this thread!
The only reason it would be spawning Node.js processes is if it's running a javaScript/typescript language server for you, but that's not a property of Zed itself, it's something any other editor would do (including VS Code). Also, the resident memory of Zed, even with multiple entire projects with hundreds of tabs open, running several language servers and multiple terminals and AI agents for me never exceeds about 900 megabytes, which is significantly less than VS Code uses even at startup.
Whatever it was that you ran into, it's likely some kind of fluke or platform-specific bug.