Real Madrid's level of performance on the pitch is very much certain to earn them the Spanish Cup trophy. They delivered a good victory against Atletico Madrid and are unceasingly seeming promising too. Their rival at the finals would always be Barcelona and whichever way they come, they'd always be the victorious team, if they noticed they've defeated Barcelona in their first meeting this season and are even performing better than Barca currently.
Barcelona themselves aren't performing near to the rate of Madrid's and so it's certain that there may be no hope for them again. Real Madrid won't take it easy on them and sternly would want to earn the trophy to themselves this season. Their performances this season have been good and top notch too and their progress shouldn't be surprising.
I also think with you. Real Madrid's performance has been much better than Barcelona so far. So I am sure that in the Spanish Cup final match, Real Madrid will be the champions. In my opinion, Real Madrid has a 70% tilt in favor of this match, which is above the Real Madrid average. In addition, Real Madrid was the better team in the second half, unlike Barca, they ignored the drop in level when facing a crisis and Real adjusted their tactics. Just look at Ancelotti's tactics now, it's very simple and there is a big difference from the previous season. Real changed their system from a 4-3-3 with 9 Benzema to a 4-3-1-2 and they were in transition but against Atletico we saw the best of them Jude, Vini and Rodrygo swapped places and came into the middle, they were a machine. Plus Brahim Diaz and Joselu and don't forget Guller. By maintaining Real Madrid's performance like when they beat Atletico Madrid in the semifinals, I am sure Real Madrid will also do the same for Barcelona in the final match.