There's a proposals repo [1] that tracks the status of features like GC. According to that, GC is phase 2, which is prototyping [2]. To get to the finish line, implementations including at least 2 browsers need to happen (this is a Web standard, so there's some browser bias in the process). It is not straight forward to see who and what are implementing a proposal, especially if not tracked in the roadmap [3]. Best advice I could give for now is to watch the proposal repo [4], or just wait. It may be a while on this one.

[1]: https://github.com/WebAssembly/proposals [2]: https://github.com/WebAssembly/meetings/blob/main/process/ph... [3]: https://webassembly.org/roadmap/ [4]: https://github.com/WebAssembly/gc