I mean semantically language evolved as an interpretation for the material world, so assuming that you can describe a problem in language, and considering that there exists a solution to said problem that is describable in language, then I'm sure a big enough LLM could do it... but you can also calculate highly detailed orbital maps with epicycles if you just keep adding more... you just don't because it's a waste of time and there's a simpler way.
The latter part is interesting. I'm not sure how the performance of one of those would be once they are working well, but my naive gut feeling is that splitting the language part and the driving part into two delegates is cleaner, safer, faster and more predictable.