Other than beating down a Luton side that really doesn't look PL standard, Chelsea have yet to lead in any match. I don't think they've been notably better than the other side in the first half of any of those four matches.
Their XG statistics are a bit of a mirage due to that Luton beatdown, the overall weakness of their opponents, and because they've spent so much time chasing matches (a game state which tends to produce more XG for the chasing team) and almost no time defending a lead (when teams tend to concede more XG than they create, even if looking to spring counters).
I think its harsh to judge Poch until he has a healthier squad at his disposal but right now its not looking good. If they were really dominating and controlling matches and just couldn't find the net it would be one thing but that's not what is happening. They are having up-and-down seesaw first halfs where they often go behind, and then they're having more of the play in second half situations where other teams are defending a lead or playing for a point.
I don't agree with this. We have dominated every single team we've played this season. It's a young team though, so we've been unable to keep focus and concentration for an entire game resulting in errors and defensive lapses. Look at the goals we conceded vs Forest (a defensive error against the run of play) and West Ham (set piece, sucker punch against the run of play and a defensive error leading to a pen). The only goal we conceded this season that was fully deserved based on how the game was going when the goal was scored was Liverpool. The first two West Ham goals are fair enough. It's how they set up to play. They beat Brighton following that exact formula.
We've not yet had a single game that was see-saw as you say. apart from Liverpool, and even that was a case of them dominating the first 25 mins and us dominating the remaining 65 mins. Teams have had bright 5-10 minute spells in each game, which have not really resulted in any goals. The eye test and the underlying metrics both support this.
Obviously it goes without saying that if you can't finish your chances, a lapse in concentration ends up becoming super costly. It adds pressure on the defence and midfield to keep clean sheets in every single game when we're always finding ourselves still searching for a goal late in games.
With all of that said though, it is utterly pointless talking about xG, xGA and xP if we stay unable to finish chances, but for now, they paint an encouraging picture and I'm reasonably optimistic that results will start to pick up. I remember when we started reasonably well under Potter but the underlying metrics were telling us we were overperforming our xG and xGA. I was happy with the early results but knew it was unsustainable unless we fixed something. Results eventually came crashing down.
Villa at home this weekend should provide a good test. It's a step up in quality from the last 3 games and they're in red hot form.
. Or loose that defensive solidarity to get more offensive players in the team that can flood the attack