[carlmr]

>As hairy as it is, COM is an example of a cross language API/ABI

I think the reverse will also be true. Any cross language API will get issues.

[pjmlp]

Indeed, example all the languages that target JVM, CLR and WebAssembly, and the missing bits between what the platform can do, what the "systems" language exposes, and what everyone else is able to expose or consume.