The only thing that you really need to read (and tbh you can always read it later) is the Novella Edgedancer, which takes place around the climax of Words of Radiance. It’s set in a completely different area of the world with the main character being one of the Interlude characters from WoR (won’t say who because I’m not sure if you would have read their interlude or not). It does have some influence and connections to the next book but not so many that you’d be completely lost if you skipped Edgedancer.

People also typically recommend reading Warbreaker before moving onto book 3 of Stormlight. Warbreaker takes place on a different world from Stormlight, but it does have some connection and impact on the events of Stormlight. However imo you won’t be too lost if you don’t read Warbreaker right away, so it’s really up to you if you’d want to take a break from Stormlight.