What's happening this season is a combination of Liverpool having a very strong team with almost everything going their way, that is, with being quite lucky.
First, the state of the big clubs apart from City: the average place of Man U, Arsenal, Chelsea and Spurs is 7th - almost certainly the worst in the last 30 years or so. The collective ineptitude of the traditional PL forces is staggering this season.
Second, Liverpool have been double lucky wrt injuries: no serious injuries to key players plus bad injuries to players of the other good teams. City have been very unlucky with bad injuries to Laporte and Sane, Stones and Zinchenko have been out for over 2 months, Rodri, Aguero, Kevin, Jesus...have missed games through injury. Manure have been without Pogba for 4 months, Rashford is injured now too. Kane is out for 3 months, Rudiger missed months for Chelsea, he's their best defender, etc.
Third, Liverpool have benefited more from refereeing decisions and mistakes, no matter whether the latter were intentional or not. City didn't have a single favourable decision in the entire first half of the season. Only after we were 14 pts off Liverpool we got 1-2 such decisions. Prior to that almost all 50/50 situations were decided against City.
Fourth, xG models show Liverpool have been luckier than the other teams. They have outperformed their xG by 17 pts in the first 22 games, which is probably unseen in any league so far. In terms of the ratio between created and conceded chances, City have outperformed Liverpool despite playing with a makeshift defence almost the entire season. Liverpool have conceded 6 goals less than expected which is down not only to incredible saves but mostly to opposition players failing to convert big chances. Think of Son and Martial the last two games Liverpool played.
Very strong team with incredible levels of luck this season.
What the xG shows is that Pep has outperformed Klopp despite the injury crisis. How come? Well, the job of the manager is to prepare his team to dominate in terms of created vs conceded chances. If you create more chances than you concede and fail to win, then individual players haven't done their job. Or you have been just unlucky.