What I dislike about the term "clean" code is that it dismiss objective criteria.

"I did it like that because it's cleaner" is a non sense. A program must be maintenable, efficient, observable, testable, scalable, performant, readable, secured. Each criteria can be objectively measured in a kind of radar diagram and can be maximized as long as it does not sacrifice another criteria. Form follows function.

Even "simple" (from KISS) is too vague, fortunately in the conference "simple made easy" Rich Hickey defines what is simple: not interleaved. simple comes from sin plex, the opposite of con plex. Not always easy to make something simple.

However I don't see anything wrong with SOLID. Separation of concerns is how a modern society or a football team works, and S brings D because specialization involves good relationships ("no man is an island" wrote John Donne ), and D is strongly related to L. I has no drawbacks.

However I don't separate data from business logic anymore (no data access layer). Business logic applies on data, not on objects that hide data. Translating a ER diagram into anemic classes while the DBA do the same in the DB does not have any value and forces to use obstruction pattern like repository. If entity classes have properties and methods (a Plane class that has a 'takeOff' and 'land' methods for instance) it is different but must most backend I see don't implement entity classes that way. Because their classes represent data, not animated concept. Player class with a shoot method might makes sense for a video game, User class with a addComment method for a CRUD app makes less sense to me.