Trent is fundamental. He has really redefined the position.
Also, he's so incredibly fortunate to emerge in the right team at the right time, to have Klopp as his manager from the very beginning, noticing his talent and encouraging him to build on his strengths and having the tactical nous to effectively compensate for his weaknesses. How many managers would have tried to make him into a conventional full-back and ruined or stifled his career? This is Klopp's superpower – I don't know another manager who is able to look so deeply into each player and help them craft the best version of themselves, while also being able to incorporate their unique skillset, whatever it is, into the larger system. It's the opposite of cookie-cutter, he is creating bespoke systems that make the best use of each individual at his disposal.
I already talked about Jota in this regard, how with Klopp's guidance he has transformed from an occasionally goal-scoring winger to a penalty box predator and even developed a seemingly new skill – his incredible heading ability. Salah, Mane, Ox, Matip, Henderson, Robbo, Trent, Firmino: they all developed into a completely unique type of player here. You could say there is no single "conventional" player, someone who plays their position in the same way as most other players, at Klopp's Liverpool. Firmino is not a striker or even a false 9, he is Firmino. Salah is certainly not a winger, he is Salah. Trent is not a right-back, he is Trent. Etc etc. I don't know if I can adequately express how deeply inspiring and overall fucking awesome this is.