I don't think the problem you encountered is due to immutability, the problem is due to the implementation, which is now improved due to better documentation and more package support.

The possibility of mutation alone will break a lot of assumptions and make program analysis a lot harder. I personally prefer no mutation at all or only when wrapped inside a cell (UnsafeCell), similar to rust. For the latter kind, we can treat the states as immutable if we don't have a cell, which can help analysis.