Not some, pretty much all of Czechia and Slovakia were much more multicultural back then than now. Germans weren't just in Sudetenland, but was a significant minority in many small towns. Same with Hungarians (just in Slovakia). Now there are almost no Germans or Jews in either of them.
Bratislava was 36% German, 33% Slovak and 29% Hungarian in the 1919 census. Now it's ~90% Slovak.