Adjective clause and the main sentence's prepositions/phrases/words

Hello my friends. I would like to make a point about adjective clauses sure today.It obviously seems that there is no rule about it as everyone/every grammar book says differently.I want something important from you today.(In almost %99 of examples, Adjective clauses come just after the word they are supposed to define.(if the word is not subject(especially it is important) ) The question is "What is the general opinion/perspective/conclusion about where to put adjective clause?"I will not share videos here because of rules, but according to some English teacher (1)"If there are some things after the word, which belong to the main sentence, you can not definitely put adjective clause in the middle of sentence, you must put it at the end. Because there some things belonging to the main sentence, you can not separate the sentence from the middle." According to others "Nothing matters, you should put it after the word, or after phrases defining the word." (2) Well. Let's look at examples which they support.(the comments which I will write are not mine.) (Group 1)
1-) I will invite my friend to the party, who is a great cook. "who" clearly refers to "my friend" and also there is "to the party" belonging to the main sentence. We can not put "who" in the middle of sentence, after "my friend". 2-) We are going to Italy at the next weekend, which is my dream.The same reason. "At the next weekend" belongs to the main sentence, we should not make the flow of sentence slower by putting it in the middle.But of course it is possible "At the next weekend, We are going to Italy, which is my dream." 3-) I am talking about the book on the desk which is about computer programming.That's the only point which they can agree with each other about."On the desk" is referring to "the book". So that's good.------(Group 2) 1-) I will invite my friend who is a great cook, to the party.That's correct. "To the party" belongs to the main sentence yes, but it doesn't belong to "my friend". If It did, we would put it after "to the party". So that's fine. 2-) We are going to Italy , which is my dream , at the next weekend.The same reason. 3-) I am talking about the book on the desk which is about computer programming.The same idea with group 1. Who is right? When examples on the Internet are examined, Group 1 seems to be right. I have almost never seen any example separated from the middle with relative clause. Thank you very much..