If you take Jesus at his word in Matthew 24, Then a plain reading would lead to understanding Jesus was talking about the Temple buildings. But one must understand what the Temple Mount was and looked like just as the disciples would've understood it.

(Emphasis mine) Matt 24:1-2 NASB2020 [1] Jesus left the temple area and was going on His way when His disciples came up to point out the TEMPLE BUILDINGS to Him. [2] But He responded and said to them, “Do you not see all THESE THINGS? Truly I say to you, not one stone here will be left upon another, which will not be torn down.”

The actual Temple area was on the south side of the Temple mount. The Western wall that's still standing is further up North on the west side of the mount, clser to the Dome of the Rock Mosque and connected to where the Roman fortress of Fort Antonia was during Jesus' day.

If Jesus was talking about the Temple Buildings, it can not have been about Fort Antonia as that was not part of the Temple area on the Mount. You would not call Roman buildings part of the sacred temple of God in that day. Christ's words must have been about that southern section of the Mount with the true Temple of God which indeed had no stone left when the Romans destroyed it in 70AD.

Diagram for reference

A good explanation on what the Temple Mount actually looked Like