All the boons Ayyubids got were suggestions that I made a long time ago and which seem to have been packed into a variant civilization to be sold to you rather than update the actual civilization. In other words, they’re selling you the same product twice.
Because of the creation of Ayyubids, Abbasids are forever doomed to remain a tech based boom civilization, whose identity will rarely intersect with Ayyubid’s gameplay. The truth of variants is that their gameplay could’ve been baked into the original civilizations to solve some of their massive design flaws. Instead, we are sold isolate solutions that keep the legacy problems for base users and it has made the whole product that is Age of Empires 4 worse overall.