Mass-metallicity relation from our stacked Hγ sample (purple stars, 6.3 ≤ z < 7). For the highest-mass bin in the Hβ sample, we also show the metallicity estimate from the higher-metallicity branch of the Sanders et al. (2024) R3-calibration curve (unfilled black star). The metallicity estimates and median stellar masses for both the samples are reported in Tables 1 and 2. The errors on the stellar mass were calculated using the 16th and 84th percentile values in the stack. While our measurements are from stellar-mass binned and stacked NIRCam grism spectra, similar to Li et al. (2025), measurements from Li et al. (2023) and He et al. (2024) were obtained using stacked spectra from NIRISS grism, measurements from Chakraborty et al. (2025), Chemerynska et al. (2024) and Pollock et al. (2025) are from individual galaxies, values from Curti et al. (2024) and Nakajima et al. (2023) are average metallicity measurements obtained from NIRSpec spectroscopy, and values from Faisst et al. (2025) were obtained from NIRSpec/IFU observations of high-mass main-sequence galaxies with [C II]158 μm observations from ALMA.