Before your first spin
A 7x7 grid runs at high volatility, so wins in Fire Portals arrive unevenly. When the free spins round starts is not known in advance. It depends on random scatter symbols on the grid, and no earlier spin predicts the next one. The result of one session is random, whatever RTP version the game runs.
Three RTP versions of Fire Portals exist, and only the game rules show which one the Neospin lobby runs. Read that rule before you compare any RTP with another game. An RTP is a long-run average over many spins, so it does not describe one session.
x10,000 the bet is the highest win Fire Portals can pay. The ceiling is reached very rarely, and no session can count on it. A higher bet raises the money paid at that multiple, but the multiple itself stays the same.