Thank you for sharing your experience! Wasm provides full process isolation, doesn't it? Do you mean that QuickJS provides cheaper sandboxing than wasm?
I’m not sure if wasm would be considered full process isolation but it does provide software based sandboxing. I’m referring to running quickjs in wasm by compiling it with emscripten.
I’ve also had luck using it in a wasm runtime thanks to quickjs-emscripten. Good if you need sandboxing sans full process isolation.