Hello Andrea, Formbi, and Guix, I got gccemacs and the no-x version to compile. They do not run entirely correctly and the closure size is quite large. That said, it feels snappy!
I submitted patches to issue 44775: https://issues.guix.gnu.org/issue/44775 If someone could investigate the retained closure references and missing references to the store, that would help a lot! Thanks and good luck, John