When we used to look at the heat maps for Mane-Salah-Firmino combo, Salah was the furthest forward, as the “Striker” stretching the defenders. He’s closer to the touch line now and is more of a creator (see his passes for Diaz against City, for Dom at United, etc). I think Olise fits in more with the latter Salah than the former. No doubt he can contribute goals and assists but I don’t see him as the apex of the attack. I think he’d be welcome but a lot would depend on Darwin and what we make of him. Olise will absolute create chances and score some, but I see him as more of a current Salah than the original Salah in the old front 3.
Maybe he can adapt his game though. He’s still very young. Worrying injury record though (“but he’ll fit right in”, etc)