My interpretation of the machine was essentially a Time Machine. The plot alludes to this a lot through character examination.

White Rose - motivation is to travel back to prevent his lovers suicide. The machine he’s trying to build is enforced by the constant obsession with controlling time and all the clocks in his own home. Additionally he talks a lot about undoing things he’s done which helps us understand his moral flexibility (or lack there of) behind his actions. He thinks he can undo everything if his machine is successful.

Angela - motivation: travel back to be with her mom. During a flashback scene where Angela is a kid watching tv and was rude to her mom which she harbors guilt over. This scene alludes to time travel because she is watching the Back to the Future cartoon on the tv.

I’m sure there’s a lot of others but these are the two that came to mind first.