Hi ! I don't know too much but I can give you some advice,
I would say that moving to another country in DP2 would definitely be a risky move if school and your final mark is important to you.
Your exchange school may not have the same courses that you are doing, so that would be extremely difficult . It can also even be very hard to pick up different teaching styles over a limited time and while the actual content may be the same, the delivery of the content may not be consistent and that may be hard for you when studying for your exams. I would say that a move would almost definitely be disruptive to your studies.
I went on a short exchange to Canada (only 1 month) in year 10 and it was definitely an amazing experience. However, it was very disruptive to me and I felt it very hard to catch up on the work I had missed and hard to adapt to the teaching styles. And that was only 1 month in year 10 so I definitely think it would be very hard for you to move to another country in your final year of schooling.
Just consider these options when making your final decision