Jhin's early game is okay, and when you pair it with stridebreaker's damage and health make you pretty strong in 2v2s and functions almost like galeforce just for aoe damage and not a singular target. You play the early as normal until you get the item, then you can farm harder and roam more.

If you gain a lead you can snowball into late game and pretty much get full build and one shot most quishies. Black cleaver makes it so you can chip down on tanks along with The collector.

However, if you're behind you should just try to split and farm up, help your team fight for objectives and wait until you have better parts of your build like your Stridebreaker + Black cleaver + Ravenous trio. Activating Stridebreaker gives every single enemy 1 stack on black cleaver, pair it with ravenous and your Q and everyone should be fully stacked if they're close enough.

Now that you are close or have full build, you can tank a lot of damage and should have around 3000+ HP, as well as around 600 AD or more. Your stridebreaker scaling should give you around 700-750 damage on a stridebreaker active. Just be careful of CC and don't get caught out of position. However, that's what flash exists for :)