My advisor has literally no idea what my research is about and I am freaking out (phd student)
But not knowing what my research is about is just plainly freaking me out!

So it seems like there are two issues here. One is the classic &quot;my advisor works in field X while I want to work in field Y&quot; problem (you will find lots of discussion of this problem if you search this site). The other is that your advisor is hands-off to the point of you being completely on your own. Given both of these factors, your decision to seek a new advisor seems reasonable. And yes, if you are unwilling or unable to work with anyone locally, then it follows logically that you will have to transfer.

The thing is that the closest school is ranked higher than mine. (Mine in the top 50, the other school in the top 15)

You may need to consider schools other than the closest one. I assume you were not able to be admitted to a top-15 school when you applied last time. Unless you've done something impressive in the last year, your odds of getting admitted are probably lower than they were last year, not higher.

Should I go to the other school and talk to the admission office? To the dean perhaps? (For my major, It is not common for students to contact prospective supervisors.

You say you are in the US, so I am surprised by the question. Graduate admissions are usually done by the department, not by the admissions office; the admissions office is usually for undergraduate admissions. The dean is also not usually involved in such things.
The only way to &quot;short circuit&quot; the usual admissions process is to find a professor who wants to work with you, and have them help you from the inside. But if you don't have such a person in your network already, this is a long-shot; most professors will just say &quot;please apply to the program and we can talk if you get in.&quot;
Bottom line: You should pursue all the options in your desired subfield, not just the closest one. But if your subfield is small and all of the programs are highly-ranked, you may need to consider other subfields, &quot;like it or not.&quot;

I don't know how I ended up here. I just found myself here!

I suggest that you reflect on this. You did not &quot;find yourself here&quot;; rather, you applied for admission in this department and then agreed to attend. There is no real harm in making a mistake; we have all made many. But it's important to recognize what went wrong so that you can avoid having it happen again.
Update: OP has since clarified that their field is Law. I cannot speak to whether this answer makes sense for law, not my area.