The Kotlin wasm compiler was basically engineered on top of wasm's GC support. Works fairly OK. As far as I understand it's essentially the same garbage collector that is also used for regular javascript.

> This is not a silver bullet. Cpp, or rust are probably still going to be the way to go.

I don't think that's necessarily true anymore. But as you say, it depends on the compiler you use and how well it utilizes what is there. Jetbrains has big plans with Kotlin and Wasm with e.g. compose multiplatform already supporting it (in addition to IOS native and Android).