I am a bit late on this but reason this didn't work is because Vanadium has a toggle to block JIT (Just in Time compilation) for code which is on by default. WASM depends on it.

JIT increases attack surface for memory-related vulnerabilities. A large portion of known vulnerabilities from browsers came from the JIT engine. Many Chrome exploits in the wild or bugs discovered in contests are from JIT bugs.

Good piece about it: https://microsoftedge.github.io/edgevr/posts/Super-Duper-Secure-Mode/

Microsoft Edge also has this toggle but has an interpreter to use WASM without JIT, but it's exclusive to them right now.