Both of them will both fight in the Champions League final this season so there is nothing to be underestimated especially a team like Real Madrid will also do everything possible to win in the Champions League final. And Liverpool is also expected to be able to come up with a better strategy so that Real Madrid can experience a little difficulty in winning this final match.
The Champions League final will be interesting. I think Liverpool (as 2nd in the League) has a higher incentive to win the final. Madrid already won the Spanish League and had a celebration, whereas Liverpool might be motivated more to win. Also Liverpool is (on paper at least) the stronger team. In one game always much can happen, but I would bet on Liverpool.