What can no one predict about Razor Shark?
Choosing a stake for Razor Shark means accepting that the bonus round may come soon or not at all. How often it comes is not known in advance. The result of one session is random, whatever the RTP shown for the game, so the RTP describes the average over many spins, not the outcome of your own session.
Checking the RTP before you play means opening the game rules, because the version Primaplay Casino runs is stated only there. Other versions of the series carry their own RTP, so compare the rules of each game before choosing.
Keeping the top prize in view means treating it as a limit, not a target. The maximum win of Razor Shark is a ceiling that is reached very rarely, and no session can be planned around it.