The parts of Big Bass Splash nobody can call in advance
Reels spin, fish drift past and the fisherman either shows up or he does not. How often the bonus round arrives is not known in advance, not by anyone; each spin is independent and the outcome of a session is random whatever the RTP says. A long dry patch says nothing about the next spin.
When the reels load, the game rules hold the figure that matters: the RTP version this lobby runs. Two versions of Big Bass Splash can sit at different numbers, so the payable return for your session is the one printed in those rules, not a figure remembered from elsewhere.
The fisherman may pull a money symbol worth x5,000 the bet, and that ceiling is real on the reels. Reaching it is a rare event, though, so treat the top win as an outer edge of this game rather than a target a session works toward.