I fixed it!
Although I don't know why what I did worked.

Turns out it was something with my English template. I made a new template and literally copied and pasted all the info from my original EN template to the my new one and changed the template ID in my app and it started working. If I change the ID back the old EN template I get those errors. So somewhere along the way something happened to that template, but it's not in the markup since I copied all that into the new template and that works fine. It must be something else somewhere in files that we don't touch.
Weird.

Shouldn't I just be able to go to mysiteaddress:4201 and the studio should come up?

yes, but it depends, if you try to access the server from another machine different than the server using the mysiteaddress:4201 then the problem can be somewhere else and related to dns or ip resolution, have you tried opening the page in the same server with localhost:4201 or 127.0.0.1:4201? if that works but mysiteaddress:4201 not then it means that you have something not configured right in your network level.