The only one really slumping is KCP and him returning to form isn't guaranteed.
Schroeder has never been a reliably good 3pt shooter. Kuzma has never been a reliably good 3pt shooter. Markieff has never been a reliably good 3pt shooter. Matthews is showing right now exactly what you should expect from him and no more. Caruso can't shoot. THT can't shoot.
Like I said over and over in the offseason, what the Lakers needed most of all is one really dependable shooter to pair with KCP. A core lineup of Bron, AD, KCP, and good shooter would be perfect for the playoffs (5th player would be Caruso, Markieff, Gasol, whoever depending on matchups). But they're just missing that one good shooter they can rely on.
Literally everyone on the Lakers is tradeable except for Bron and AD. Caruso probably shouldn't be traded cause he's worth more to the Lakers than to anyone else, KCP likely won't get traded because the Lakers expect him to return to form (though of course they would give up KCP if it were necessary to grab a star).
I think a package of some combination of Kuzma, THT, 2nd round pick, and either Schroeder or Trez could potentially land a solid 3+D or elite shooter, with potentially a backup PG or defensive big included in the trade to fill out the Laker lineup, especially if Schroeder or Trez were leaving.