I think here's validity to the position debate but that's not the issue right now. The problem is he seems to have fallen out with Pep, and even when playing he's miles off it.
We can debate whether LW is his best position long term, but he's produced there for nearly half a decade now. Last night he looked like he'd never stepped foot on a pitch before.
I hate saying this because I love Phil, but he gets too much slack on here sometimes. He's one of our best players and absolutely has the talent to be genuinely world class, but he needs to step up. I'm expecting to get criticism for this but take his performance/whatever is going on with Pep plus the off field incidents of the past few years, stick it on Grealish/Mahrez/Cancelo/etc. and I'm not sure they'd have made it out of the stadium safely.
I think this issue, whatever it is, will pass and he'll go on to have a legendary career at City. He's and incredible footballer and seemingly a good guy as well. But I do think it's time for him to take the next step. He's 23 in a few months, which is young but not that young in footballing years. He's been in the first team and with Pep for over half a decade - there's really no excuse for squabbling with the manager and popping up in the news a few times year.