Umm... Looks like the Go + Flutter Nostr client loads fast enough for normies on real devices (Go as a static lib on iOS in this video).
https://video.nostr.build/ed283b89cc701a826c49c6d73711283d7c4d9ddf69edb767ae6566f7a1cd3bb9.mp4
Equivalent demo for the web (Go as a web worker):
https://wasm-worker-testbed.pages.dev/