C# 11 addresses the first issue by adding the required fields/properties: such members must have their values set upon instantiation.
For the second one, the ^1 index stands for length-1, which is the last element's index. With ^0 the compiler should implicitly add 1 every time an index is accessed.
As for me, I take the good bits that I like and ignore the rest now. I resent only two changes. Firstly, eliminating null values for classes was a mistake, and you're trading one class of error (null data) for another (placeholder/default data). There's no plus as far as I can tell. Apps with the second error scenario are in an unknown state and that's not something you want lasting for too long. The second change I dislike is that the inverse indexing syntax starts from 1 instead of 0 to access the last item. That's idiotic.