Earlier quoted context omitted.
Having the sandboxed Google Play services would be wonderful. I'm currently using LineageOS with microG and Aurora store, but quite a lot of apps do not properly run with microG. Having some kind of fallback alternative in a second user or even better a work profile would be great.
What apps dont run for you? Everything is working fine for me. Are you also using Magisk with the DenyList enabled?
Because of this I'd love to see GrapheneOS' sandboxed Google Play Services shims I'd love to see integrated into LineageOS.