The XC60 is Volvo's more important model. It shares a tremendous amount of the larger XC90 platform. Since the engine and electronics are largely the same, most of the larger software gremlins have been sorted. As a former SPA platform owner (2016 XC90), my pro-tip is that Volvo updates software rather frequently and you'll want to let the dealer know if you're experiencing any issue as there is likely a software update to remedy it. This could be anything from the obvious control of screen and infotainment but to the unobvious things like temperature controls, unusual alerts, even how hard the transmission shifts--all software managed.
Regarding fuel economy on the Drive-E engines. They're small but powerful. Drive with a lead foot and they'll drink fuel like a teenager drinks Red Bull, which is to say excessive. My previous Volvo was the wonderful 2016 XC90. It achieved an average 16MPG under my lead foot. My current Volvo is the V60 Polestar with a similar Drive-E engine... we're operating at a more dignified 22 MPG despite the lead foot being oh so heavy.