The InShot alternative that keeps the transcription on your device
It would be easy and wrong to say InShot uploads your video. It does not: the editing, the drafts and the export happen on the phone. It would be equally wrong to say everything stays there, because the auto-caption feature sends your audio to InShot's servers to be transcribed. Both halves of that sentence matter.
Montaj has no such split. WhisperKit runs on your device, so the audio for the captions never goes anywhere, and neither does anything else.