I like your way of thinking. Java meaningfully abstracts away memory management concepts. But would I be better off if did know memory management? Marginally. There were a few times when these concepts were useful.

I would call Java effectively “sealed” because 99.9% of the times you don’t need to go deeper into abstraction layer.

LLMs don’t have this property. You do need to understand some syntax and some low level design. So I wouldn’t call it “sealed”. That doesn’t mean it is not useful. You just need 10% or so of the understanding of Java syntax and other concepts.