Best-fit architecture of the TOI-421 system for the northern (top) and southern (bottom) configurations. The stellar spin-axis is the black arrow extending from the north pole, with the stellar equator plotted as a solid black line. The stellar disk is colored as a function of its surface RV field. The green and orange solid curves represent the best-fit orbital trajectory for TOI-421 b and c, with normals shown as arrows extending from the star center (the planets do not undergo stellar occultation due to the eccentricity of their orbits). The thinner colored lines show orbits obtained for orbital inclination, semi-major axis, and sky-projected spin-orbit angle values drawn randomly within 1σ from their PDFs. The star, planets (black disk), and orbits are to scale. We note that the two planets were not simultaneously transiting in our observations.