Having a 6 point lead over Girona and 8 points over Barcelona has never made Real Madrid feel safe. If you really watched the last match against Sevilla, Real Madrid and all their players were really frustrated when Sevilla made them unable to score. Ancelotti and his players didn't want to lose points which would likely make the two rivals closer, but luckily Luka Modric with his quality was able to score the winning goal.
So far Ancelotti has had no other choice but to continue relying on the same players in many matches. He has difficulty rotating because many of his players are still injured, as a result this will drain a lot of the players' energy which will likely reduce their performance due to fatigue. A busy schedule is clearly a problem until the time bomb explodes.
La Liga still has 12 matches remaining, until the 2023-2024 season. Currently, Madrid is 6 points ahead of the team below them, namely Girona, and 8 points ahead of Barcelona. I agree with what you said, winning 6 points does not make Real Madrid safe in the 12 remaining matches until the end of this season. In the match against Sevilla, Madrid had quite a difficult time breaking through the opposing team even though the match was held at the Santiago Bernabeu. Luckily, Luca Modric was able to break his team's deadlock and at the same time brought Real Madrid to full points in the match against Sevilla.
as you said, the Madrid players struggled to score a goal against Sevilla. there were many opportunities they had from 6 shots on target. in total, Madrid had 16 shots. 1 Valverde shot hit the post, and they only had 1 big chance. well, the absence of several core players has had quite an impact on Don Carlo's squad in terms of scoring goals. what is certain is that Don Carlo had to prepare a different strategy and system when Bellingham was injured. In fact, so far there is no certainty when Bellingham will return to play with the regular Real Madrid squad. Likewise with other mainstays, Joselu is also absent due to injury.
Apart from that, several Real Madrid players are also still suffering from injuries, including Courtois as the main goalkeeper. To move safely and continue on the right track, Don Carlo must adapt the system and strategy so that his team can be consistent. Apart from that, Madrid has matches in another competition, namely the Champions League. Without several core players, Madrid cannot be careless when playing against Leipzig in the second leg. Moreover, Madrid only won with an aggregate of 1 goal. Apart from that, I also agree that the absence of several players can drain other players which can reduce the performance of the Don Carlo squad. Therefore, as a very experienced coach, Ancelotti must prepare his team's squad when playing match after match that his team will play.