I was super disappointed in Pikmin 4

Agreed, I'm a big fan of Pikmin, been playing since the Gamecube, I even have the rare Pikmin 2 for Gamecube. Pikmin 4 disapointed me.

I enjoied p4 but the graphics, mechanics, and story in p3 is better imo

I agree. For me it was the excessive dialogue in 4.

IMO As far as having a story and overall progression, Pik. 3 is better. However there are a lot of things Pik. 4 does right that P3 doesn't. Eg. with P3's final boss, it's hard to tell if you're progressing due to to the regeneration. P4's boss has very clear progress. Both good.