There are type system gotchas. My favorites have to do with integers in place of JS's double-only numerics, the treatment of undefined and nulls, especially in arrays.
The LLM's are just fine at AST translation, though they might inject their quirky preferences if you don't watch them carefully. Suggestion: use the LLM's, but interactively, to translate one script at a time, starting with the simpler ones. Tell the LLM to explicitly call out potential issues. Manually review each, and incorporate the issues and preferences you learn into the prompt. If all goes well, the process will quickly converge on a cut and paste job, but don't be tempted to fully automate it if it's a hundred scripts -- different matter if it's thousands.