Would require rewriting a lot of functions in TypeScript, but iirc there's nothing in her codebase that can't work inside an Angular (or react, bite me) app, could then toss said app into Electron, and despite definitely being a resource hungry POS it'd still probably run better than than whatever JavaScript engine is used for this. Ideally it'd also be easily distributable for other platforms like HTML games as well.
Then again, haven't worked with it, but that other game made it work decently well in Godot, with mod support too.
but converting Java to C# feels like a sin, a GDScript brings out the most negative of emotions