"because clause" verses "because of noun" verses "because noun"

I have been thinking about a feature of English that seems to have emerged very recently. "because" and "because of" really are two different words: the former a conjunction the latter a preposition.

I came inside because it was raining.

I came inside because of the rain.

However, there seems to be a cool, hip trendy way of speaking that sort of blurs the two:

I flunked my mid-term because covid.

I am absolutely soaking because rain.

I was wondering if this really is a new grammatical form in the English language, or if there is some history behind it, and if there are other conjunction/preposition pairs that have suffered the same fate.

I also wonder if there should be a comma after "because" in this novel form, it just seems to demand a rhetorical pause.