I faced a related dilemma when I finished my CS degree: to work as a full-stack dev or to work on more foundational technology (and actually use what I learned in my degree). My experience is that the "foundational technology" area is more "research-oriented", which means you get to work on projects where LLM's don't help that much: writing code in languages that have little data in the LLM's training corpus, coming up with performance benchmarking approaches unique for your application, improving a workload's throughput with insights derived from your benchmarking results and your ingenuity, etc. Had I gone down the full-stack path, I think I'd be worried now.