> LTS is more relevant if there was any kind of compatibility that was broken

Do we know 100% for certain that this isn't the case? No.

In fact it would be naive to think a rewrite of this magnitude wouldn't introduce new bugs and/or unexpected changes in behavior.

> Nothing to me suggests they’re being careless here.

Plenty of reasons suggest this including the lack of an LTS or any kind of thought put into such a massive transition.