64 bit is correct. The latest processors, both Intel and Apple Silicon, are 64 bit. Where are you seeing the info that seems incorrect to you? I wouldn't be concerned unless you see "Intel" somewhere, in which case you may have the wrong version.
- The download file should end in "macos-arm64.dmg"
- If you select the OBS app in Finder and choose File > Get Info, the "Kind" should be "Application (Apple silicon)"
- If you open Activity Monitor and search for OBS, the "Kind" column should show "Apple"
