There are no shadows or transparent textures and only low poly models, yet I only get maybe 2fps. I've built webgl racing game that did >50fps on a $50 phone [1]. There's something seriously wrong with your tech stack. [1] https://www.youtube.com/watch?v=okg61OOFUdQ
This may be a compatibility problem. On my phone it seems to run at 60fps.
It's slightly better in chrome/edge at maybe 15,20 fps but still un-pleasant.