It’s still a really large discrepancy. I would guess something is broken somewhere. What is the webgl frame rate on native Mac? Have you tried running those webgl demos with chromium?
Note that I haven't really optimized it yet. Certainly there should be low-hanging fruits, but I don't dare to get them as it is good enough for me as GNOME is no longer laggy and I know some overheads cannot be eliminated.
If I have to do graphics-intensive workload, I would simply run it on macOS or buy another accelerator as M1 is not the best performant graphics accelerator in the market anyway.