Wouldn’t the third temple be the spiritual one mentioned in the book of Revelation?
Right on.
But you can’t convince the Jews of that.
I don’t mind seeing them build the third temple just to get the muzzies off that mountain.
I don't think the one mentioned in the Revelation is the same place (temple) spoken of by Jesus:
"When ye therefore shall see the abomination of desolation, spoken of by Daniel the prophet, stand in the holy place, (whoso readeth, let him understand:)" (Mt. 24:15 AV).
There, Jesus warned the reader to look at Daniel's prophecy, but apply it to the future coming of the Antichrist, of whom Antiochus IV Epiphanes was a type, who defiled the Second Temple. Speaking of the Seleucid leader (Antiochus/Antichrist?):
"For the ships of Chittim shall come against him: therefore he shall be grieved, and return, and have indignation against the holy covenant: so shall he do; he shall even return, and have intelligence with them that forsake the holy covenant.
And arms shall stand on his part, and they shall pollute the sanctuary of strength, and shall take away the daily sacrifice, and they shall place the abomination that maketh desolate" (Dan 11:30-31 AV).
No, the temple will be physical so the Beast can sit in it. The 7 year trib starts when Israel signs a peace treaty. The Jews will immediately start to build. I’m told they already have the implements ready to go. The Beast will declare He is God from there to begin the final 3 1/2 years.