IDK on Android. But on PC i just had to activate WebGPU in the about:config in Firefox to make it work.

edit: Yeah and it works really well for what it is. Seeing thousands of other cars on your map is really fun. I highly recommend to deactivate collisions though. Otherwise its constant carnage. The netcode for this slopped together port of a 20 years old game is obviously pretty poor. Especially because there isnt regional instancing. But there is fun to be had with a few online races. I played through UG2 probably four to five times through the years but never had the chance to play the multiplayer. So i'm pretty happy to have had the chance to experience that for once.