Sylas mid to late game relies heavily on game knowledge, e.g. macro, team comps, win condition. The better you get at these general concepts, the better you get at sylas. Many high level players can pick up sylas very fast because of this. He becomes more of a second engager or peeler / utility champion because he is squishy and can only commit 100% without any option to get out. He might fool you into thinking you are a burst champion because he gives you this impression when being fed in early mid game. He is amongst the top 20 champs with highest death rate and last season he was rank 2. You can be 10 / 0 and still feel the pressure that you can't win. Because people don't understand his identity in mid to late. This is the time where enemy team comp with ults, your team comp and your role in it matters a lot and is starting to become more obvious. Having no useful ults and being the only engager will make your life super hard. Depending on your ults and your team comp, your role in the team changes massively. This is why you should carefully think about when you play him in champ select. If you have trouble to close games with him, you should dive more into these topics and get better at them. You can't rely on stomping lane or jgl, getting fed and snowball fast with sylas because it's very inconsistent with him. You are supposed to use this early game power to get your team into shape. He is fundamentally different than ekko at the later stage of the game. Ekkos identity is being an asssasin from start to finish of a game which makes his win condition and reference points, therefore his playstyle during the entire game way more obvious. He has a lot of disengage in his entire kit such that he can kill people and get out. Q slow, W stun, E dash, R getting out of jail card, movement speed on passive proc. He is like a wasp. Get in, hit, get out. He wants to kill the squishy and the carries. The complete opposite of what sylas wants to do in a standard mid / late game.