Here is a list of approved programs for JWST - https://www.stsci.edu/jwst/science-execution/approved-progra...
You can filter by cycle & purpose - I think you want GO 4 then look at Exoplanet Atmospheres and Habitability?
Related, but here is the Spectra of K2-18 image - https://webbtelescope.org/contents/media/images/2023/139/01H...