mm2 / il2cpp / urp takes 10x longer to load than in Mono

About 5 times slower, actually. The thing is that IL2CPP doesn't use c++ code that comes with MM. Instead it converts c# code into c++ on it's own instead. Unity boasts that there is almost no performance loss compared to code written in natively in c++, but seems they are not exactly correct about it. It's still WAY slower than real c++ code.

The only thing I can recommend is to use c++ compiler configuration in Release mode and avoid using developer builds. It will speed things up but still will be far from perfect.

I'm not sure it's quite that simple - it seems more like a couple of orders of magnitude slower. On first load I'm showing a loading screen until all neighbouring tiles are generated and goes from about three seconds in mono builds to several minutes in IL2CPP. I hear on the discord this is specific to URP?

I'm interested in moving to IL2CPP because the native C++ stuff doesn't work at all in linux or mac builds.