Future of going to university in Germany? How will my exchange year influence my college application

Hi everyone-
I’m new to this site so I’m sorrry if I’ve messed anything up on this post. I am a sophomore at a top high school in Washington state. Next year, for the my entire academic junior year, I’m going to be an exchange student living in Germany (Hamburg area) and going to a German gymnasium. I’m interested in the possibility of studying in Germany as an undergrad university student, and I want to go into an Architectural or Sustainability field.
More information:
-My exchange program is Rotary Youth Exchange, what I heard from them is that most colleges consider them to be a merit scholarship
-I have a 3.6 GPA, but I take very challenging classes, all honors or a year ahead
-I will leave this year with three years of French class, only because I skipped a year between French 1 and French 3
-In terms of ECs I do improv, have been on cross country, and have generally been very involved in both my school and city community, I’m on boards that organize community events with the city council and I volunteer a lot

My main questions are:
How do I match up with an abitur in terms of meeting the requirements to enter German university?
How will my having spent a year in gymnasium influence my application to German universities?
What universities should I apply to? The only one I’ve done much research on is Munich Technical University, but it seems very selective.
Would it be better to take the ACT or the SAT, and when, since I’ll be abroad for all of junior year? (Former exchange students can help out here)
I will definitely apply to many USA schools, how will my current state of academics + my exchange year look on an application?

Thanks