TS23/McDonald and FIES/NOT strike again. Two new warm Jupiter systems and outer companions in a third

Warm Jupiters (gas giant planets with orbital periods of P about 8-200 d) are thought to be largely unaffected by the tidal interactions that can erase information about the dynamical histories of hot Jupiters. Their orbital eccentricities (e) and stellar obliquities are therefore expected to be preserved, making them valuable probes of giant-planet formation and migration. Our aim is to identify and characterise transiting warm Jupiters in order to expand the sample of well-characterised systems and enable further studies of giant-planet formation and migration. We analyse TESS transit photometry together with ground-based radial velocity measurements and perform a joint fit of the photometric and spectroscopic data from the TS23 and FIES spectrographs to determine the planetary and orbital parameters. We report on the discovery and characterisation of two new, transiting warm Jupiters; TOI-5120 b (M p = 1.23 plus or minus0.05 M Jup, R p = 0.969 plus or minus0.017 R Jup, P = 24.91645 plus or minus0.00002 d, e = 0.10 plus or minus0.02) and TOI-5699 b (M p = 0.25 plus or minus0.03 M Jup, R p = 0.996 plus or minus0.015 R Jup, P = 22.01850 plus or minus0.00004 d, e = 0.30+0.09-0.08). We also refine the parameters of the known warm Jupiter TOI-2158 b (M p = 0.87 plus or minus0.04 M Jup, R p = 0.899 plus or minus0.015 R Jup, P = 8.60079+0.00002-0.00001 d, e = 0.028+0.013-0.014). In addition, we detect an outer planetary companion, TOI-2158 c (M p i = 1.62 plus or minus0.13 M Jup, P = 414.5+1.5-1.6 d, e = 0.54 plus or minus0.04), and identify a long-term radial velocity trend that may indicate another planetary companion on a wide orbit. The diverse architectures of these systems, in particular the presence and absence of outer companions, highlight the range of dynamical pathways leading to warm Jupiters.