Comparing the Civs steals the joy they bring for their various reasons.
Civ 1 was unlike anything else and so legendary it created the 4X genre.
Civ 2 had the best espionage until an expansion for 4. Civ2 also defined the scope for all future Civs.
Civ 3 was fine. Resources were a good addition and tile quirks, like Floodplains on top of another base tile like desert, helped bring tons strategy and gave the ability to grow Tall.
Civ 4 was probably peak Civ for many people, especially including DLCs.
Civ 5 removed unit stacking and made happiness a resource.
Civ 6 emphasized the city development aspect and brought back the climate stuff from 2, 3, and 4.
They are all good but they are not collectively suitable for every person. Civ6 is amazing but it took me literally 30 hours to finally have it click. I also have 550 hours in Civ 6 and over 1200 in Civ 5. CiV is also a high water mark but it overshadows the real value and fun in 6.
It’s a shame most folks will ignore us and say 6 was bad for being too game like.