That's basically what I've done at work on my embedded project.

Object pools, with indices and generations. Way, way easier than meddling with raw pointers, cheaper than shared_ptr/weak_ptr and no clean-up required when deleting stuff because the stored generation won't match the new object's generation. You can even make that default-constructible if you increment the generation on instantiation too (so that only even generations are alive) and hide it all behind high-level abstractions with C++.

Though my knowledge of these techniques come from 2000s video game architectures, as games like GTA: Vice City are known to use it.