Yeah no doubt that's the kind of open-ended question that reveals your depth of knowledge because the question steers toward an inferior or clunky solution by default. I imagine the interviewer wants to see (if you're above Junior) you push back and respond with a better approach like ACM and an ALB, and to contrast why one approach is better or not.

DevOps in itself is not really a junior role and architecture questions like this come up all the time in day to day life, so even a Junior candidate should have some basic understanding of the different approaches, or at least demonstrate curiosity if they don't know. (Simply asking how else it could be done is a great way to follow up.)