I prefer combining two or three different generations, starting from the 1990s up until the present day.
GK: Gianluigi Buffon (era: 2001-2006)
CB: Alessandro Nesta (era: 2000-2007)
CB: Sergio Ramos (era: 2013-2017)
RB: Philipp Lahm (era: 2010-2015)
LB: Paolo Maldini (era: 1997-2001)
DM: Claude Makélélé (era: 2000-2002)
CM: Xavi (era: 2008-2012)
AM: Kaka (era: 2005-2008)
RM/RW: Lionel Messi (era: 2010-2015)
LM/LW: Cristiano Ronaldo (era: 2013-2017)
CF: Ronaldo Nazario (era: 1996-1999)

Substitutes:
GK: Manuel Neuer (era: 2012-2016)
CB: Virgil van Dijk (era: 2017-2020)
LB: Roberto Carlos (era: 1997-2002)
DM: Patrick Vieira (era: 1999-2004)
CM/AM: Steven Gerrard (era: 2004-2008)
LW: Neymar (era: 2014-2017)
CF: Thierry Henry (era: 2002-2006)

but the second Galacticos had to wait for five years until their first UEFA Champions League trophy, while the first one only needed two years until they got the first and only UCL trophy in 2002. the issue is the lack of balance within the team: too many attacking outlets and almost-no strong defensive-minded transfers to replace Makelele, Karanka, Campo and Cambiasso.