One of the main questions in Astrophysics is whether there are other Earths in the Galaxy. Our project is observational and technically prepared to address this question and lead to a significant progress on our understanding of the physical properties of planets, brown dwarfs, and stars, their formation mechanisms and evolution. We will conduct searches for planets in the habitable zone of low-mass stars and around young stars, we will study exoplanetary atmospheres, the planetary-host stars, and will explore star-planet interaction. Our methodology will be based on precise radial velocity measurements, planetary transits, and direct imaging techniques. Our project brings together researchers from four different institutions with demonstrated expertise in all of these aspects. The scientific coordination will guarantee the success of the proposal. All the nodes are part of the CARMENES consortium, and the CARMENES Legacy-Plus survey, both aiming at studying planets around M ​​stars, which is co-led by one member of our project. We are also part of the ESPRESSO GTO consortium, which has data from the most stable spectrograph in the world, and the next-generation ANDES instrument for the ELT. In addition, we also lead the GTCAO system and the GRANCAIN instrument, which will provide diffraction-limited images at the GTC, and the EUCLID Independent Legacy Science group that will enable direct imaging of planets and brown dwarfs. As part of our interest in the identification and characterization of low-mass planets around ultra-cool dwarfs and obtaining high-contrast images of exoplanets, we lead and are also involved in the development and science preparation of future projects such as MARCOT and the ExoLife Finder 3.5-m prototype Small-ELF.