There is a subtle difference in focus, apart from the differences in formality. Using “was” is more distant and neutral. Using “get” is more personal and focuses on the loss. Police talking to a crime victim. What was stolen? (Yes, an impartial request for information) What got stolen? (No. ) I’m sorry that your car got stolen. I’m sorry that your car was stolen. (Both sound fine) Don’t park in the alley unless you want your car to get stolen. (Very natural. Conveys concern) Don’t park in the alley unless you want your car to be stolen. (OK, but sounds oddly formal and detached)

Yes, you would always want to use "was stolen" that is the proper way to say it. Got stolen is more "slang" and not a proper use of English. Hope that helps.

They have the same meaning. "Got stolen" is used often but would not be appropriate in a formal setting. "Got stolen" would be a more colloquial way to say "was stolen."