I don't think this final will require both teams to decide victory on penalties, although it's possible but I really don't expect it to happen. But I have doubts about that. I didn't expect the final to result in a lot of goals even though it looks like both teams can score. Liverpool have hopes of winning the match, so do Real Madrid but if I had to choose then I think Liverpool looked more deserving of the favourites tonight.
Real Madrid will have more difficulty with their older players than Liverpool but Real Madrid actually have some good young players such as Valverde, Rodrygo, Vinicius, Camavinga. They can be helpful players and substitutions for them if the match goes to extra time.
Although Liverpool have a younger age in average so they will have more advantage if the final goes to extra time, it does not mean The Kop will easily to beat Real Madrid in extra times. Their opponent are experienced enough to play defensive aggressively and wait for opportunity to score decisive goal if The Kop play carelessly in last 30 minutes of extra time. We see it in football many times. A dominating team will want to finish a match without penalty shoot-out but sometimes they were beaten by very late goal of opponent.
Honestly, the record of Real Madrid in this Champions League is very well whenever the match has gone to extra time. So, I think it is not going to be easy for Liverpool to win if the match actually ends up going to extra time. Liverpool is going to try to end the match before extra time because they almost had some problems with injuries and they obviously don't want any of their important players to get injured.
But, as you have said they also have good substitute players ready. On paper, it looks like Liverpool is stronger but we have to understand Real Madrid has experience on their side. And we also cannot forget about Benzema.