PLATOSpec's first results. Planets WASP-35b and TOI-622b are on aligned orbits, and K2-237b is on a polar orbit

The spin-orbit angle between a stellar spin axis and its planetary orbital axis is a key diagnostic of planetary migration pathways, yet the mechanisms shaping the observed spin-orbit distribution remain incompletely understood. Combining the spin-orbit angle with atmospheric measurements has emerged as a powerful method of studying exoplanets that showcases the synergy between ground- and space-based observations. We present the Rossiter-McLaughlin effect measurements of the projected spin-orbit angle (λ) for three gaseous exoplanets using the newly commissioned PLATOSpec instrument on the E152 Telescope at La Silla Observatory. For WASP-35b, we determine λ=1+19−18 deg, demonstrating PLATOSpec's capabilities through excellent agreement with HARPS-N literature data. We provide the first spin-orbit measurements for TOI-622b (λ=−4±12 deg, true spin-orbit angle ψ=16.1+8.0−9.7 deg), revealing an aligned orbit consistent with quiescent disc migration. For K2-237b, we find λ=91±7 deg and ψ=90.5+6.8−6.2 deg, indicating a nearly perfect polar orbit, which suggests a history consistent with disc-free migration, contrasting previous studies inferring disc migration. TOI-622b populates a sparsely populated region of sub-Jovian planets with measured spin-orbit angles orbiting stars above the Kraft break, while K2-237b's polar configuration strengthens tentative evidence for preferential orbital orientations. All three systems are compelling targets for future atmospheric characterization, where these dynamical constraints will be vital for a comprehensive understanding of their formation and evolution.