Does not overlap in Luke 21.
“This is the third time I am coming to you.
In the mouth of two or three witnesses shall every word be established.”
2 Corinthians 13:1 KJV
luke 21 is the same event just adding seperate details , same with mark 13 we’re meant to take all three gospel accounts ( johns being for a different purpose ) in to have a fuller understanding of three witnesses remembering Matthew was the only one present being the only
apostle of the three.
beginning here in mark
“And Jesus answering said unto him, Seest thou these great buildings? there shall not be left one stone upon another, that shall not be thrown down. And as he sat upon the mount of Olives over against the temple, Peter and James and John and Andrew asked him privately,
Tell us, when shall these things be?
and
what shall be the sign when all these things shall be fulfilled? And Jesus answering them began to say, Take heed lest any man deceive you:”
Mark 13:2-5 KJV
Here in luke
“And as some spake of the temple, how it was adorned with goodly stones and gifts, he said, As for these things which ye behold, the days will come, in the which there shall not be left one stone upon another, that shall not be thrown down. And they asked him, saying,
Master, but when shall these things be?
and
what sign will there be when these things shall come to pass? And he said, Take heed that ye be not deceived:..
Luke 21:5-7 KJV
and here in Matthew
“And Jesus said unto them, See ye not all these things? verily I say unto you, There shall not be left here one stone upon another, that shall not be thrown down. And as he sat upon the mount of Olives, the disciples came unto him privately, saying,
Tell us, when shall these things be?
and what shall be the sign of thy coming, and of the end of the world? And Jesus answered and said unto them, Take heed that no man deceive you.”
Matthew 24:2-4 KJV
It seems it must be important because he is telling them and us , us
not to be deceived.
my own thought is it’s not meant to choose one account but accept all three so we have a fuller understanding of what Jesus said as each account holds some different details of what was said . that’s just my own thinking we all seem To have different ways of understanding which we are entitled to.
They are really
Consistent in what he’s saying but offer details in each that the others don’t completely hold , and the epistles later bear it all Out with further details pertaining to his coming.
my own view is we should just let it all
In and let it become what we believe and not try to make others see what we do but just share it amongst believers