Before the spin, the result is still open
On the reels, three, four or five Scatter symbols start the free spins, and nobody can tell before a spin when they will land. How often the bonus comes is not known in advance. The result of one session is random whatever the RTP, so a short session can end far below the stake and a long one can end above it.
Each spin on the reels follows a single RTP version. Which version Mybet Casino runs for this slot is shown only in the game rules, and those rules decide the RTP you play on. Check them before a session starts.
Round wins on the reels stop at a fixed cap, and the maximum win of Bigger Bass Bonanza is a ceiling reached very rarely. Read it as the limit of the game, not as a result to expect.