Sibling comments talk about a 2024 stdlib change which broke some people because they had written code which depends upon an inference and with a new enough stdlib that inference is now ambiguous so the compiler requires that you disambiguate or your code doesn't compile with the newer library.
So, that's not a breaking change in the language. It's annoying, and ideally shouldn't have happened, but in contrast the two languages you praised (C and C++) have in the last ten years made real breaking changes to their actual language and as expected the same people who insist Rust isn't "stable" shrug off the extra work from that as No Big Deal.
As someone who wrote C for decades and now writes Rust instead it's very striking how much worse the "bit rot" is in reality for C.