Can I charge my iPhone overnight even after the warnings from Apple to not charge overnight?

Another misleading article. The editors must have been desperate to fill some space at the last minute before publication.

The article can be summed up in the quote below.... (buried in the article, of course where few users would ever see it).... as follows:

The tech giant hasn't asked us to stop charging our phone overnight altogether, but it has flagged that we need to make sure we're not charging our phone somewhere where it's going to overheat.

Yes, maybe the misleading title of article grabbed a few more viewers, which was the goal of the editors.

Can you provide a link to the Apple "warning" that you mention?

I can find nothing from Apple in this regard, although I can find several documents that recommend charging overnight. That's what Optimized Battery Charging is all about.

Where did you see this warning, it most certainly wasn't from Apple. Apple has never said to not charge it overnight, in fact, they highly recommend it.

You apparently didn't read the whole article. Nowhere does it say not to charge overnight directly, it says not to charge it overnight where it can overheat.

Here is the direct quote from the article -

"The tech giant hasn't asked us to stop charging our phone overnight altogether, but it has flagged that we need to make sure we're not charging our phone somewhere where it's going to overheat."

And yes, that is very good advice from Apple

No, it absolutely was not from Apple, just more misinformation from the media.

Apparently (from some news site)

There are also "news sites" that maintain that the earth is flat.