Before the first spin, the bonus timing stays open
Choosing to spin Angel vs Sinner means accepting that the bonus round comes when the reels decide, not when you plan. Nobody can tell in advance how often the free spins start, because each spin is random. The RTP describes an average over a very long run, so the result of one session can be far above or below it. Plan your money with that in mind.
Deciding whether the RTP suits you starts in the game rules, because the version running in this lobby is shown only there. Read them before the first spin, and check which version they name.
Knowing the ceiling helps you judge the stakes before you begin. The maximum win of Angel vs Sinner is 15,000x the bet, and that ceiling is reached very rarely. Hitting it depends on the random outcome of the spins, so no session can be planned around it.