I have no clue why conventional wisdom holds that Jewish people built the Pyramids of Egypt, when in fact, the oldest portion of the OT was written almost 400 years after the most recent pyramid.
This isn't intellectually honest or sound to explain history like this. Perhaps a people from East of Egypt - modern day Israel and surrounding areas - were enslaved to build the Pyramids (or a pyramid) as were people to the South and West of Giza. And the narrative that Jews built it came many centuries later.
There's supposedly some heiroglyphs of Jewish babies being fed to aligators in Egypt, and we know that they're Jewish because they are circumcised. However, even the Egyptians were circumcising their males!
Please give me your opinion or insights to this matter.
You may be interested in answers from previous discussions on the topic. The general scholarly opinion is that there is no credible evidence that the Jewish people built the pyramids.
How was it possible that Jewish people built the Pyramids, but the last Pyramid was around 1764–1759 BCE, but the oldest part of the Old Test. was written in 1400 BCE
First, the bible is explicitly about a time earlier than its explicit authorship. Second, I don't think any scholarship would put any of the bible that early, definitely not the parts with the Exodus. Third, the bible doesn't claim the Jews/Israelites built the pyramids--the only named things are two cities.
My suspicion is that the awareness of pyramids as 'things built in Egpyt' helps this, along with cultural depictions of Israelite slaves building them.
Where did you hear that there are hieroglyphs depicting Jewish babies? Are you referring to the animated movie The Prince of Egypt? I've certainly never heard of such a thing and would be interested if you have a scholarly source.