I'd say, they are all doing the same, just in different domains and level of quality. "Understanding the topic" only means they have specialized, deeper contextualized information. But at the end, that student also just autocompletes their memorized data, with the exception that some of that knowledge might trigger a program they execute to insert the result in their completion.
The actual work is in gaining the knowledge and programs, not in accessing and executing them. And how they operate, on which data, variables, objects, worldview or whatever you call it, this might make a difference in quality and building speed, but not for the process in general.
> only means they have specialized, deeper contextualized information
no, LLMs can have that contextualized information. understanding in a reasoning sense means classifying the thing and developing a deterministic algorithm to process it. If you don't have a deterministic algorithm to process it, it isn't understanding. LLMs learn to approximate, we do that too, but then we develop algorithms to process input and generate output using a predefined logical process.
A sorting algorithm is a good example, when you compare that with an LLM sorting a list. they both may have correct outcome, but the sorting algorithm "understood" the logic and will follow that specific logic and have consistent performance.