I remember having similiar issues with the Switzerland download. I also tried several times and it seems to have stopped at 80%. But at one point, when I got frustrated again and went back to the regions screen, it said "installed", although it never reached the 100%.
Maybe you can try to go back from the downloading screen after it reached 80% for a short while and before it crashes? Make sure you don't do anything else when downloading (in case you did). In the end, it worked with me. Using an iPad pro 10.5.