I cannot put Guardiola as one of the greats when he's shown he can only do a job where he's not at the biggest club in the league or richest team in the league, (barca and bayern, or a petro dollar state one.)
The Barca job with the talent at his disposal that he inherited with Messi, Henry, Xavi, Ineista, Puyol, Xavi, Pique, Eto'o Busquets, quite a few managers would have won just as much with what he did with that team, Enrique a manager on the tier below won a treble with practically the same players and Suarez and Neymar added 2-3 years after Pep left Barca.
Bayern at 3 seasons he couldn't add another CL with that all conquering side under Heynckes, and that is with including Lewandowski as soon as he arrived.
When Grealish is signed, his spending will be £839 million at City , going into his 5th season and still City are the biggest underachievers in the history of the European Cup, laughable with that outlay they have only gotten to one final, bottled it and before that got knocked out of the mighty and great european giants of Spurs, Lyon and Monaco.
Mourinho won a European Cup and Uefa cup with Porto in successive seasons
LVG won a European Cup with a team of kids.
Rafael Benitez won 2 La Ligas with Valencia in the era of the Galacticos of Real Madrid and when Barca had Rivaldo, Ronaldinho and Kluivert and won a Uefa cup, he also won a CL with a very much unfancied side very much like Mourinho's Porto were.
Ranieri winning the PL title with Leicester.
I put those managerial exploits above as more impressive then winning CL with Messi, Iniesta and Xavi, winning consecutive titles in the 1 team bundesliga and spending the GDP of sudan every season to flat track bully 80% of the PL.