ISIS was on its heels and retreating for quite some time; it was always our policy to have Iraqis and Kurds take the lead, which gave the whole thing more legitimacy. We always were in an advising and air-support role. From Obama to Trump.
The only thing that changed was an alteration of the ROE that relaxed the rules about targeting, allowing a higher tolerance for civilian casualties. As a result, Raqqa fell a bit faster, but many more innocents died. Maybe thousands, but probably hundreds.
That’s it. All major operations were already planned out by January 2017.
I know a little about this.