Modric's quality is very good. There are no players who can replace it regularly. So as long as he's still fit enough then I think it's not a hindrance. The management and coach certainly understand the condition of the players, so at this time Modric also started more matches from the reserves. Anceloti has understood that his age will not be effective to play for 90 minutes continuously. Belingham's arrival has helped Anceloti, and he already has a replacement. Although I think Belingham needs friends if it is true later Kroos and Modric
No one doubts the quality and contribution of Luka Modric to Real Madrid and he has proven this so far. I think there are many other young players in Ancelotti's squad who have developed a lot and maybe that is the reason Luka Modric plays more from the bench and is no longer a starter. This is normal because if Luka Modric does not renew his contract, it will not cause the club's performance to decline because they have found the right replacement.
The arrival of Belingham and several other midfielders has also really helped Ancelotti's current team, so that they managed to occupy first place in the standings. Belingham can play with any midfield that Real Madrid has and I don't think that will hinder his performance in making a contribution.