Acknowledgements. We are grateful to an anonymous referee of their kind remarks and constructive comments on several key-points of the paper. Their review has helped significantly to improve the organisation and clarity of the paper. This work presents results from the  European Space Agency (ESA)  space mission Gaia. Gaia data are being processed by the  Gaia Data Processing and Analysis Consortium (DPAC). Funding for the DPAC is provided by national institutions, in particular the institutions participating in the Gaia MultiLateral Agreement (MLA). The Gaia mission website is https://www. cosmos. esa. int/gaia. The Gaia archive website is https://archives. esac. esa. int/ gaia. The full acknowledgements are available in Appendix C. through the European Leadership in Space Astrometry ( ELSA) Marie Curie Research Training Network  ( MRTN- CT-2006-033481 ), through  Marie Curie  project  PIOF-GA-2009-255267  ( Space AsteroSeismology & RR Lyrae  stars, SAS-RRL), and through a  Marie Curie Transfer -of-Knowledge (ToK) fellowship  ( MTKD- CT-2004-014188 ); the  European Commission 's  Seventh Framework Programme  through grant  FP7-606740  ( FP7-SPACE-2013-1 ) for the  Gaia European Network for Improved data User Services (GENIUS)  and through grant  264895  for the  Gaia Research for European Astronomy Training  ( GREAT-ITN ) network; -the  European Cooperation in Science and Technology (COST)  through  COST Action   CA18104  ' Revealing the Milky Way with Gaia (MW-Gaia )'; -the  European Research Council (ERC)  through grants  320360 ,  647208 , and  834148  and through the  European Union 's  Horizon 2020 research and innovation and excellent science programmes  through  Marie Skłodowska-Curie grants   687378  ( Small Bodies: Near and Far ),  682115  (Using the  Magellanic Clouds to Understand the Interaction of Galaxies) ,  695099  (A sub-percent distance scale from binaries and  Cepheids -CepBin ),  716155  ( Structured ACCREtion Disks -SACCRED ),  745617  (Our Galaxy at full  HD -Gal -HD ),  895174  (The build-up and fate of self- gravitating systems in the Universe) ,  951549  (Sub-percent calibration of the  extragalactic distance scale in the era of big surveys -UniverScale) ,  101004214  ( Innovative Scientific Data Exploration and Exploitation Applications for Space Sciences -EXPLORE) ,  101004719  ( OPTICON-RadioNET Pilot ),  101055318  (The 3D motion of the  Interstellar Medium  with ESO and  ESA telescopes -ISM-FLOW ), and  101063193  ( Evolutionary Mechanisms in the Milky waY ; the  Gaia Data Release 3 revolution -EMMY ); -the  European Science Foundation (ESF) , in the framework of the  Gaia Research for European Astronomy Training Research Network Programme (GREAT-ESF ); -the  European Space Agency (ESA)  in the framework of the  Gaia project , through the  Plan for European Cooperating States   (PECS) programme  through contracts  C98090  and  4000106398/12/NL/KML  for Hungary, through contract  4000115263/15/NL/IB for   Germany , through  PROgramme de Développement d'Expériences scientifiques (PRODEX)  grants  4000132054  for Hungary and through contract  4000132226/20/ES/CM ; -the  Academy of Finland  through grants  299543 ,  307157 ,  325805 ,  328654 ,  336546 , and  345115  and the  Magnus Ehrnrooth Foundation ; -the  French Centre National d'Études Spatiales (CNES) , the  Agence Nationale de la Recherche (ANR)  through grant  ANR-10-IDEX-0001-02  for the ' Investissements d'avenir' programme , through grant  ANR-15-CE31-0007  for project ' Modelling the Milky Way in the Gaia era' (MOD4Gaia) , through grant  ANR-14-CE33-0014-01  for project 'The  Milky Way disc formation in the Gaia era' (ARCHEOGAL) , through grant  ANR-15-CE31-0012-01  for project ' Unlocking the potential of Cepheids as primary distance calibrators' (UnlockCepheids) , through grant  ANR-19-CE31-0017  for project ' Secular evolution of galaxies' (SEGAL ), and through grant  ANR-18-CE31-0006  for project ' Galactic Dark Matter'  ( GaDaMa ), the Centre National de la Recherche Scientifique (CNRS) and its SNO Gaia of the Institut des Sciences de l'Univers (INSU), its Programmes Nationaux: Cosmologie et Galaxies (PNCG), Gravitation Références Astronomie Métrologie (PNGRAM), Planétologie (PNP), Physique et Chimie du Milieu Interstellaire (PCMI), and Physique Stellaire (PNPS), supported by INSU along with the Institut National de Physique (INP) and the Institut National de Physique nucléaire et de Physique des Particules (IN2P3), and co-funded by CNES; the 'Action Fédératrice Gaia' of the Observatoire de Paris, and the Région de Franche-Comté; -the German Aerospace Agency (Deutsches Zentrum für Luft-und Raumfahrt e.