Neither will more advanced work be replaced by 2027. End of story.
High schoolers are already not widely employed for knowledge-based work. It's almost all physical labor. The few knowledge jobs among my peers in high school were tutoring and call centers, both of which are arguably replaceable with LLMs today.
But "replaced" isn't really the right frame either. In my very physically-constrained industry I can't point to any specific job titles that have been replaced by "AI" but I do see a meaningful volume of labor being taken on by ML-dependent technologies like robotics and AR, which leads to increased productivity overall which leads to bottom line results that the users are seeking.
So to me it seems reasonable that we will see this with more advanced work. The better the AI tools get the more work they will be able to assist with, including the making of better AI tools.
And regarding your other point:
> both of which are arguably replaceable with LLMs today
Arguably, but they are not. That‘s my point.