I tried that car at https://emre-aki.github.io/tmp3d/
It's about 10 fps on this non-gamer 2018 laptop. Try use the option to run the game in a new tab.
And maybe it's worth to look into that js assembler thing:
https://developer.mozilla.org/en-US/docs/WebAssembly
If I remember correctly, it can use the GPU, and do 3D vector calculations in a single processor instruction (like shaders do). Sounds perfect for a software renderer. You might end up faster than webGL.