Amanda Angelika wrote:

It's hard to be 100% certain,

But you seem to be anyway - as in your later: "But it certainly ..."

there is the other theory that the pyramids
were built somewhat earlier by an advanced race that was here before.

For which there is no evidence at all.  Did the Egyptians dig it all up
and destroy it, except the pyramids of course ?

There is plenty of evidence of the actual peoples that lived in the
area for a thousand years or more before the great pyramids were built
and it shows a gradually increasing sophistication, plus a few failures
that they learnt from.

But it
certainly seems unlikely they were all built by the Ancient Egyptians.

What makes it 'unlikely' ? that other ideas are just more interesting ?
that you _want_ it to be unlikely ?