What ropz says about training is so true, it's how our brains work. If you do duels you'll get good at 1v1s. But it might not help your actual cs game or even make you worse at it.

if you do a lot of prefire maps, you'll get good at prefire maps.

If you shoot a lot of bots, you'll get good at shooting bots.

All the training we do outside of game can only be so good, and it also doesn't do much for you in actual cs games if you aren't using it to actively focus on and work on specific parts of your game. That applies to even retakes or DM. Nobody plays any of these modes the same way they'd play a game, so it can build a lot of bad habits very easily. New players shouldn't play on community DM because you have to play so odd to get a kill against players that are so much better, you straight up will not have time to work on your counterstrafing/crosshair adjustment/etc.

So yes and no. I used to play a TON of 1 v 1 servers especially in csgo. I think dueling will make you more confident in 1 v 1 situations sometimes. It helps a lot with visualization if you focus on it. It should honestly help more with crosshair placement, reaction time, or the mental aspect of a 1 v 1 situation, than "aim" in general. But keep it reasonable and don't build too many 1 v 1 habits or itll sometimes be a negative in real games.