IQ is a pretty arbitrary measurement, but I think a modern yankee in egypt would indeed have problem solving skills beyond their peers. Our education, formal and social, is quite a rapid process in the modern world and we basically give kids a free ride until around 18 so that they can focus on education rather than being forced to do menial labour.
I think that as physical beings we're pretty similar to our ancient selves (though maybe a bit worse off with all the PFAS and similar pollutants in our systems and the lack of immunity tuned to the environment) but our problem solving skills are tuned to a much more complex level of problem.
Whether that level of problem solving is materially useful is a whole different topic.
I don’t know the historical record for ancient Egypt, but I imagine we are way bigger and way smarter on average because of childhood nutrition and lack of parasites - see also, North Korea.
Smarter feels like a bad word to use - I specifically dialed into problem solving because I think that's one place we can accurately differentiate but "smarts" is an incredibly broad concept. We're better at certain things because of specialization and long education but worse at other things because we're obviously not training our motor skills to do different things from birth - it's like folks who can skin mangos in a single cut, it can be learned but most of us aren't going to learn it.
Ancient Egypt did have public schools and a semi-meritocratic scribe class so formal education was a thing which makes it easier to compare in contrast to areas that revolved entirely around apprenticeship like the more nomadic contemporaries would be.
Also, we do have a much more balanced diet growing up but if we did travel back to ancient Egypt there might be dietary issues trying to maintain our extra mass - the lack of access to diverse fruits and vegetables might wreck havoc on our bodies... you can look to extreme contemporary diets for any evidence of that you'd like to see.
I think that as physical beings we're pretty similar to our ancient selves (though maybe a bit worse off with all the PFAS and similar pollutants in our systems and the lack of immunity tuned to the environment) but our problem solving skills are tuned to a much more complex level of problem.
Whether that level of problem solving is materially useful is a whole different topic.