If someone denounces this baseline (and not fails to follow it, but denounces it), there’s not much left to a claim of following Christ.

And that is not an objective statement that’s verifiably and objectively true. It DOES depend on personal opinion and interpretation. Other Christians might say other stuff in the Bible is more important. Like killing homosexuals. Or burning witches.

There is no clear definition of an ideal Christian. Never was. Never will be. Every century has its own view on what Christianity has to be like, we just happen to live in one which tends to agree with your views.

In other words, according to your statement, there were almost no Christians a few centuries ago, which is verifiably untrue.