I think a lot of DM’s in the Alonso, Pirlo, Jorginho mould. You’d need a box to box CM who was capable of covering the running like Mascherano, Khedira, Gattuso, Kante. You’d also need very good defensive backs, as if your DM loses the ball then there’s no cover for your CB’s. I know good CB’s are useful, but with this type of DM - you don’t need so much centre backs that are good on the ball as the holding mid can link the midfield and defence - it’s about pure defensive acumen.
I’d say there’s basically no chance.
In the 60 years the big ears has been around, the side with the second most wins of the European Cup is Milan who have won it seven times.
It would require at least eight CL’s to overtake Madrid, assuming Real don’t win another CL - which there’s every expectation they will soon. They are also set up well to prosper in the long run.
In the last 20 seasons, there have been ten different CL winners. Only four sides have won the CL more than once since 2004, and Barcelona are the only side to have won the CL thrice in the last 20 years.
I’m basically ruling out anyone with less than five CL wins and I don’t think Bayern, Milan, Liverpool or Barca are much better positioned than Real to win another CL
Based on the above, I’d probably go back and say guaranteed no chance.