If he takes you to the PL and CL trophies this season and hits 40 goals.
Will he be the greatest ever Liverpool player ? (Considering what he’s already done)
Nah, he'd have to stay at Liverpool for at least 5 more years while keeping these numbers up and consistently win things to be able to be called our greatest ever player.
Ronaldo (just guessing here) won everything he could've won at United but isn't even in the conversation (correct me if I'm wrong), just because of the longevity side of it.
Salah is well on his way to put himself clear of our other recent great strikers like Torres and Suarez though, which in itself is an incredible feat. Would probably already make an all-time Liverpool XI and when all is said and done he could be one of our all-time greats. Greatest ever, I'd say he won't achieve that just because he'll eventually leave or regress to the mean.