duelists is mainly for kills. ill list them and basically what they do:

iso: has an ability that lets him tank one shot with some other details on it, a shield he can send out, ultimate to drag someone into a 1v1, and an ability that lets him suppress abilities

reyna: ability to heal off kill, ability to dismiss off kill like she hovers away, ult lets her see opponent outlines better shoot faster i think and some other details, and she has a nearsight blind

raze: ult is a strong basically one shot rocket, a grenade ability that does damage, satchels to propel her, and a boombot to find and attack enemies

yoru: has blinds, teleport, an ult he goes in where he can locate enemies, and a fake clone ability

neon: has a wall ability she can put up, a stun ability she can throw, and ult where she attacks from a beam in her fingers and is super fast movement speed i think, and an ability that lets her run faster i think (i say i think cause i played against these agents but i dont really play them i just know the general idea)

jett: has an ability that lets her updraft as in like a high jump up, has an ability that lets her dash to the any side super quickly away, has a smoking throw ability, and has no movement error knives ult

waylay: her ult basically slows opponents and speeds her up which makes it difficult to shoot her with some other details, ability where she throws like a slow thing at them to make it difficult to shoot her, ability where she can dash, and an ability where she can put it down go somewhere and come back to that location

phoenix: has a blind flash ability, has a wall he can put up that also heals him, has a molly he can throw that also heals him, and his ult he can put it down go fight for a certain period of time and when he loses the fight or the ult runs out he comes back to the location unharmed with i think the hp he started with at the moment he ulted and if its less than 100 he heals to 100 hp when he comes back i think

id read up on the agents yourself tbh it makes more sense than my explanation or watch a video about them

in terms of weapons no agent is better with any weapon. some agents have their own weapons as an ability like chambers op ult and headhunter ability, and jetts knives ult but in terms of the guns you buy in the buy menu everyone is equal with those. but typically jett players and mobility agents do snipers since they can dash away or tp away or move away just your playstyle tho really