The abomination (antichrist) makes Jerusalem (the harlot) desolate by getting the 10 kings to nuke her (Zechariah 14:12》Revelation 17:16-18》Revelation 18). He is called the abomination because after his death (Isaiah 14:11/Daniel 11:22/28/Revelation 13:3,10) and resurrection (Isaiah 14:19/Daniel 11:29/Revelation 13:3,11) he is described as being an "abominable" branch (Isaiah 14:19) The third temple that he sits in (2 Thessalonians 2:4) and makes his palace (Daniel 11:45) will be viewed spiritually desolate from the get go (Matthew 23:38/Isaiah 1:11-15) even before he sits in it. BUT it is called the temple of God because God ordained it (Zechariah 4:6) to fulfill His will (Revelation 17:16-17). And that will is (a) drawing out & purifying of the tribulation Israeli remnant church. of Pergamos at Satan's seat (Revelation 2:12-17/Revelation 11:7-8/Daniel 11:45/Zechariah 13:8-9/Daniel 11:32-35/Isaiah 37:31-32/Romans 11's grafted back in natural branches) & (b) throwing down the harlot so she is never found again (Revelation 18:21).
The temple that he sits in can't be allegorical for a couple reasons. First, if you allegorize the temple into being a christian's body, you just denied predestination & eternal security by claiming that our body can be defiled by the beast. Secondly, you also just contradicted Revelation 13:8 & Revelation 17:8. And if you claim that the temple being sat in in 2 Thessalonians 2:4 is just any old human body, believer or unbeliever, then you just espoused occultic, new age belief that "we're all God's children" but the Bible does not teach that (John 8:44/Acts 13:48). And plus this view contradicts 2 Corinthians 6:14-18 which likens unbelievers bodies to temples of idols.
So clearly this points to a literal 3rd temple in Jerusalem. "But God does not want animal sacrifices" you say. Absolutely right; and that's not why He is allowing a 3rd temple. And in all honesty, you could also argue that God NEVER wanted animal sacrifices (obedience over sacrifice has always been His plea). "But a 3rd temple would be blasphemy". Who raises up the antichrist to power? God (Revelation 17:16-18). What does antichrist then turn around & do? Blasphemes God. So what exactly is your point then about a "blasphemous" 3rd temple? It seems that many in "reformed" circles love pounding the pulpit about "God's sovereignty"...until God's sovereignty clashes with what the reformed ones think makes sense through their theological indoctrinations.