Frankly, I think Islamophobia here is weaker in OTL. Even with the attack on the Russian Foreign Ministry, it will still be weaker.
The Russians, unlike the Americans, have a more nationalistic and specific vision for Muslims, and not as comprehensive as the Americans
(The Russians were very tolerant of Kazakhs, Turks, Central Asian Muslims, Azeris, and Russian Muslims, Slavs, who often showed loyalty to the Russian state.)
And with Muslims, Arabs, Africans, Persians, Kurds and Albanians, who were their allies throughout the Cold War.
But they are very cruel to the Chechens and Circassians who have shown their tendency to rebel against them
And hostility towards the Turks because they are a Western ally and a threat to them
So I don't see that changing with September 4th
The effect I might see is that this time the Chechens have a bad international image, so no one would mind cracking them down hard.
I don't think we will see an invasion of Afghanistan but more support for the Northern Alliance (via Ashgabat)
So I think the attack will have a weaker effect than September 11th
Except for encouraging airline passengers to resist the hijackers
The damage is that Putin will struggle to find a brilliant diplomat to become foreign minister (if Lavrov is among the victims).
And the victims will be less because the building, unlike wtc, will take longer to collapse and being wide may only destroy the upper part while keeping the lower part intact.