I’ll preface this by saying that English is not my mother language and I’m sorry if this isn’t the right community, but I didn’t find a more appropriate one.
Last year I started to notice more and more people on YouTube for example using the verb “to put” without a preposition – like “Now I put the cheese” – which sounds very weird and kind of feels wrong to me. Is this really used in spoken English and is it grammatically correct?
No for most people because “put” would require two complements - the object and the place. (It’s a lot like a ditransitive verb, even not being one.) And in this case the place is missing, you’d expect it to be at most replaced with an adverb (e.g. “now I put the cheese there”).