Experiment: can we improve key types we get from map iteration?

[uint]

Currently, the key types are always something nested, confusing, and not very ergonomic.

Custom struct instead of tuple

Maybe it would make sense to replace the tuple with some sort of a custom struct. That would let us be a little more descriptive with what's what, and provide helper methods.

Avoid the wrapper in some cases

Maybe we can avoid some nesting when dealing with a terminal inner container, and so on. Research?