It's interesting when you compare the quality of teammates over Messi and CR7's careers:
1) Messi's best teammates were a higher quality overall IMO compared to CR7's best teammates. Xavi, Iniesta, Alves better than Ramos, Modric, Marcelo IMO. Which could be a reason (not the full reason) why his peak years are so damn stellar.
2) CR7, on the other, didn't play in a bad team (at the top/CL level) from 2006-2018. Was surrounded by United's best team ever (or second best ever) and then Modric, Ramos, Marcelo, Benz, Bale, Kroos, Pepe, Varane etc. at RM. Messi has had suspect CL teams in 06-07, 12/13, 13/14 and basically from the EV era onwards.
3) When they've had average/bad teams, Messi has done better than CR7 in the CL. Compare the last 3 years. Messi took care of Napoli, United, Lyon easily and put in a good effort v Pool and PSG. Got destroyed by Bayern but I think Juve would have been destroyed by them too. CR7 did great v AM but other than that, has been meh. Maybe Ajax was decent. Porto and Lyon huge stinkers.