See also:

https://github.com/eternal-flame-AD/pow-buster - Browser extension that already used WASM to accelerate the anubis solver, among others.

https://github.com/kasper93/anubis_webgpu - Browser extension that uses webgpu, for another order-of-magnitude speedup (depending on your GPU of course).

afaik argon2 should make the GPU less helpful

Argon2 is already GPU-accelerated.