Pep has been in the game for far longer time than Zidane, who only managed Real Madrid and didn't manage other clubs unlike Pep so this comparison doesn't work. If we're saying Pep only won it with Barca who are the best team in history, Zidane has also only won it with Real Madrid with also one of the best squads in history and is yet to test himself in CL with other teams.
I think people exaggerate the CL issue really. Winning CL is pretty damn tough. You don't just need abilities but also a lot of luck along the way. It's a cup competition, anything can happen in a tie, and beside the first few seasons at City, his teams have always been in advanced stages and challenging for it. He reached the semis 3 times with Bayern, the final last season and now in the semi this season. He only failed to reach semi final 4 seasons out of his 13 years of management. The league is a better measurement of how a team consistently perform, not cup competitions. Winning CL is nice and all but you don't just need to be good to win it.
There's no manager who's fully perfect - SAF himself also had his issues and his tactical mistakes in crucial games anyway - , but Pep being an idealist and wanting to always win using his own style is what defines him as a manager and why he'll end up being one of the elite in football history. He changed the landscape of football when he first appeared with Barcelona and proved that his style can be successful everywhere. A lot of people expected him to fail to implement his style in the Premier League but he completely dominated it.