I wrote the Circuits programming system for Rec Room, and we took a similar approach: keeping the core logic free of Unity dependencies so it could run and be tested on CoreCLR.

The results were similar as well with significantly better performance outside of Unity. There are also secondary benefits. Unity’s API surface is huge, and it’s easy for code to accidentally entangle itself with engine details in ways that confuse or constrain other developers.

By isolating the core in a separate DLL, we only expose Unity concepts where they’re actually needed, and we enforce that boundary with tests. That logic constraint ended up being just as valuable as the performance gain