Resolution convergence for cosmosTNG. Left: Halo mass function (HMF) for three different resolutions. The dashed lines show the corresponding TNG100 resolution run. Right: Stellar mass function for three different resolutions and gray markers for observational data. The HMF converges down to a characteristic turnover at the low-mass end below 10^8.5 M_⊙ for cosmosTNG-1. The cosmosTNG HMF matches well with its respective TNG100 pendant except for M_vir > 10¹³ M_⊙ where we find an excess of massive halos in cosmosTNG. The stellar mass function generally appears to retain shape at increased resolution, but systematically increasing by up to 0.2 dex per resolution level at fixed stellar mass.