I'm not too bothered by his lacklustre performance today, as fatigue from the internationals is a temporary issue and he'll soon be back to full strength. I do think some work needs to be done on his positioning and the team's tactics, though.
If he's playing on the wing, he needs to be contributing to the team's width. Fine to come inside, especially with the ball, especially while a full-back is overlapping, but he can't just abandon the wing. Especially in the first half today, Gvardiol was in possession high up on the left but his team-mates were too often too far away from him, leaving him needing to make riskier decisions while outnumbered by opponents (that he handled this well doesn't make it less of a problem). Phil was on the edge of the box, directly behind Haaland, and no-one was in the left half-space.
I much prefer Phil in the middle than on the wing, but playing him there while our other options are all available too brings its own challenges as I'm not convinced the balance of the side works against most clubs (especially those with a threat on the break) when we have both Phil and KDB central.
I'm not knocking his workrate or tracking back at all, but Phil's mindset, like Kev's, is to always be on the front foot and pushing up the pitch. When our midfield is those 2 + Rodri, there's too big a space in front of Rodri, making it harder both to move the ball forward and intercept a counter-attack.
Phil is KDB's eventual successor, but something has to give if we want them both in midfield. They're both fantastic players but the team isn't quite right in that configuration.