I imagine writing native javascript workers could be acceptable in some cases, but ofc, you’d just have to duplicate that logic. Might be worth it if there are just logs of calculations going on (I’m even imagining modelling the params and instructions of those calculations into a common type - basically a string which then you can parse on both C# and js, so that you can at least reduce some duplication).
However, and this might be the case for some people, I only needed support for async/await via the UniTask plugin, and [this]( https://discussions.unity.com/t/665972 page-2#post-8400342) plugin allowed me to do that without webgl threading (it’s basically all done on the main thread, scheduled via the regular Update)