The Call of Duty series are actually really well designed games. It's a shame that its playerbase is such as it is because it leads to many people, players and devs alike, being dismissive of its design because it's just seen as "the normie popular shooter" and it's become taboo to copy features or design styles from it. See BF6 for a recent example of a game being ragged on for "turning itself into Call of Duty".
Despite this fact, I firmly believe most modern FPS games would benefit greatly from taking inspiration from CoD. They just have to skip the part where Activision weaponizes the developers competence to make them competently develop money making features instead of fun making features, so to speak.