score:2
The question seems to be finding something that simply isn't there.
Consider other translations of this verse, e.g. CSB:
From now on, then, we do not know anyone from a worldly perspective. Even if we have known Christ from a worldly perspective, yet now we no longer know him in this way.
It's talking about how we should relate to other people, at a spiritual rather than physical level.
There's not the slightest insinuation that any of Jesus's teachings are no longer relevant.