Lol, adcoms at top colleges aren’t club bouncers, who like your look or deny access. They look for what matters to them. Plenty of teachers write disengaged letters. “Johnny has been my student in xxx. He’s also in band and plays soccer.”
That’s a front end problem. Not a reason to look for less info on a student and turn holistic into stats based process.
And if an adcom faces a poor letter, the comment might be, “LoR adds little.” Then, the rest had better make up for that. And they aren’t grading the quality of a letter. Rather, looking for the perspective it adds. The relevant perspective.