One huge problem is that with code the usual way of ensuring maintainability is to revisit old code and rewrite parts of it as needed, in order to be able to maintain it properly.

One huge problem with no/low code solutions is that people usually think that this doesn't need to be done for no/low code solutions, only for code solutions. But solutions using nodes in order to build stuff also need to be revisited, refactored and thought of as abstractions.