For context, my team has spent the past few years porting Unreal Engine 5 to WebGPU and WebAssembly - we have a multi-threaded renderer as well as an asset streaming system that fetches in at runtime asynchronously (as needed) so users don't need to download an entire game/app upfront. This also frees up needing to have the whole application in memory at once. We've also built out a whole hosting platform and backend for developers to deploy their projects to online.
You can learn more about SimplyStream here:
Website: https://simplystream.com/
Blog post: https://simplystream.com/create/blog/latest