Militão Is just returning from a very serious injury, I think he should be given time. Obviously Alaba is unreliable at the moment, Nacho has gone.
I read that Real want Yoro from Lille, a young CB with a lot of potential. Regardless I think the title race will be a lot closer this season, Barca have a lot of very talented young players who are another year older.
Defense is currently Ancelotti main focus for them to improve before the season starts, Last season their defense was actually quite good and was the defense with the fewest goals conceded in La Liga, but it seems like Ancelotti is still not satisfied with their defense line which often experiences pressure when facing an aggressive team so that bringing in a new defender will be an effective solution for Madrid at the moment, Militao is one of the defenders that Madrid has relied on so far, but the injury suffered by Militao actually meant that Militao had to be absent from the Madrid squad last season, even though currently Militao has recovered, but if Ancelotti forces him to continue playing next season, it is certainly not impossible that the injury will recur, although Madrid have several central defenders currently in their squad but I dont think they are worthy enough to replace Rudiger or Militao in main squad.
I doubt that Alaba will be able to return to normal and it looks like his injury is quite serious because up to now there has been no sign that he will be able to join training. Maybe Militao seemed to have played several times at the end of last season but he still needs time to get everything back together. Now the only fit left is Rudiger and the latest news is that Vallejo has returned to Real Madrid after his loan contract with Granada ended.
For Leny Yoro, Real Madrid continues to try to get the Lille player to come this summer because if not Real Madrid will have a central defender crisis next season. Apart from that, previous rumors were also linked to William Saliba from Arsenal and to be honest, if Real Madrid can get these two new defenders it will make their way to defend the La Liga title as well as the Champions League easier.
Several of the players you mentioned, except for Nacho, who has left, don't seem to be fully expected to be able to guard Madrid defense next season, so Ancelotti is starting to try to recruit new players, although so far we haven't seen any players who are very close to joining Madrid, by the way, Madrid previously tried to recruit Alphonso Davies from Munich, have they officially signed him now? although Alphonso Davies is a left back, he actually performed quite well when coach shifted his position to center back when Nagelsman coached Munich.