Unfortunately, most movies from Apple’s media store [1] [2] in Austria have German audio and/or possibly original foreign audio, but rarely additional (dubbed) audio languages.
Each country has its own store with its own content for that region, and its own language support, that the supplying studios have decided on. Decisions can differ by movie title and policy can differ by studio. There is no method to add languages to what is offered. You can ask the studios for wider support, but I expect them to be motivated what they think that “most consumers” will want, not individual buyers.
When available, the default language can be changed as described here:
Change subtitles or audio languages for videos in the Apple TV app - Apple Support