LOC doesn’t inherently make things unmaintainable slop, as long as you have strong abstractions (which Linux certainly does)

one could argue that most Linux distros have billions to trillions of LOC and their abstraction is packages, which are kinda a level of abstraction higher than libraries, which are just a level of abstraction higher than a folder of util functions

things being “not my code” doesn’t mean it’s not part of your system