Late to this thread, but will share my older brother’s experience. He was a Rotary exchange student in Europe for his senior year in high school and decided to return home to take a second senior year so he would be able to take AP Calc BC and have time for college apps and essays. He applied to 5 schools and got accepted to his first choice, NYU, with significant merit and graduated a few years ago. He said that had he not taken a second senior year, he would not have had time for the college app process during his exchange year and likely would not have ended up at NYU.
Acclimating to a new culture/language while having to go through the college application process from afar at the same time would have been very difficult, in his opinion. YMMV.