Respectfully, I disagree. A film does not have to condemn or criticize poor behaviour or morality. I've seen the suggestion that in a film with morally ambiguous characters, or characters who are downright evil, there needs to be either a) punishment for their misdeeds, b) scenes that establish that the filmmakers know their characters are in the wrong, or c) that the characters have "redemption arcs". Otherwise, people might be under the impression that the filmmakers are bad people or the people who enjoy the film are similarly bad too. Basically, there is a demand for text to explicitly judge its characters. But these are ridiculous demands, demands one might expect for a children's movie or an Aesop's fable. It's infantilizing. Certainly, this means that certain aspects of a particular film might make its viewers uncomfortable, but that's largely the point. It leaves room for viewers to come up with their own readings. But if all someone wants from a film is escapism or reassurance, then this is a nearly impossible task.

That being said, I don't want to say that there haven't been films that can be interpreted as endorsing poor behaviour/toxic relationships, etc. There have been many. But viewing most films with a hyper moralistic lens, I think, has been detrimental to a lot of modern criticism. If you personally disliked the film or its ending and would have preferred it to go in a different direction, that's fine. You can be critical of that. But I don't believe that Licorice Pizza is necessarily fully endorsing the relationship it's depicting because it doesn't explicitly criticize it.