Kel is right and it has little to do with Modric. They played the best football of any team in the group stages by a long stretch. They then met two notoriously packed sides in Denmark and Russia but still made a big effort, and they played dazzling stuff against England after that. No team has played more consistent high quality football this tournament. No team has looked more like an actual football team either. Most of France's brilliance has been the product of individual moments by contrast, mostly from Mbappe and Pogba.
Probably a minorit - borderline hipster - opinion but I'd argue that Japan was probably the team that ran them closest when it comes to tactically advanced and attacking football.
What's it about their attacking play that you'd class as 'tactically advanced'? They use a very rudimentary attacking style : get it to the wings and cross or hoof it to Mandzukic and look for knock downs.
A tactical advance attacking play is what I'd class Belgium's approach against Brazil: a strikerless set up with both Hazard and Lukaku on the wings and the Brazil CBs scratching their heads about who to mark. Belgium have generally played better and more attacking football than Croatia IMO, England have also been much more positive in their play too. And if we are talking about only the group stages, Mexico were much better to watch IMO.