Long-run RTP before, one session after
Choosing to play Big Bass Halloween means accepting that the bonus round may come early, late or not at all. How often the Free Spins start is not known in advance. The result of one session is random, whatever the RTP. The RTP only describes the long-run return across a very large number of rounds, not what your own session will bring.
Checking the game rules comes before you set a bet, because they name the RTP version this game runs. That version appears only in those rules. Read that section once, then compare it with the figures above before you decide how much to stake.
Deciding how much a big result would mean to you starts with the ceiling. The maximum win of Big Bass Halloween is 2,100 times the bet, a limit reached very rarely. Plan each session around the stake you can afford to lose, not around that top figure.