AFAIK I think Igalia is/was working on WasmGC support for Webkit/Javascript Core [0]. Not sure about the status though, it's tracked here I think [1]. It says it's updated earlier this month, but don't know of the progress made.

[0]: https://docs.webkit.org/Other/Contributor%20Meetings/Slides2... [1]: https://bugs.webkit.org/show_bug.cgi?id=247394

Oh, https://bugs.webkit.org/show_bug.cgi?id=272004 looks promising

"All Wasm GC features are implemented, and the feature can be enabled once typed funcrefs (https://bugs.webkit.org/show_bug.cgi?id=272003) are enabled"