Plan your session around what stays unknown
Winning clusters vanish and new symbols tumble into place after every win, and the bonus round starts when enough scatters land on the grid. How often that happens is not known in advance. The result of one session is random, whatever the RTP, so a long quiet run and a sudden bonus are both normal outcomes.
The reels play the same 7x7 grid whichever RTP version is live, because the difference sits in the maths behind each spin. Which version runs on this site is shown only in the game rules. Look there before you start, not on the reels.
Tumble chains on the reels can run long, but the maximum win of x25,000 your bet is a ceiling reached very rarely. Multiplier spots double across a chain and keep building through free spins, so the big figures come from long runs. Treat the top figure as the upper edge of the game, not an expected result.