At the moment, I think I would still say this:
Pope
Alexander-Arnold Gomez Maguire Chilwell
Henderson Rice
Sterling Grealish Rashford
Kane
Picking the best England squad is difficult enough though, let alone the first XI. Certain positions are much easier than others in my opinion though.
Alexander-Arnold, Maguire, Chilwell, Rice, and Kane are probably as close to certs as we can get for most games, probably Gomez too when we look at the remaining CBs even though I don't think he's amazing - but he does compliment Magurie the best. This will probably be a somewhat unpopular opinion from me, but I reckon that if England wants to win something (provided they fail to win Euro 2021 as expected) then the following need to be removed from the England starting XI and maybe squad all together: Pickford, Walker, Dier, J.Henderson, and probably Southgate sacked as the manager as well.
The goalkeping situation is a strange one, I'll admit Pickford hasn't been that bad for England but I am sure he will be more of a liability than Pope or D.Henderson in the future.
There are some great full backs at the moment, but I think Walker is coming to a point where he should focus on playing for just Man City. I always feel like he is going to give something away despite how good he is (probably underrated to be honest). There's just so much competition in that area, I think he is going to be the one to miss out with Trent preferred as the attacking full back and Wan-Bissaka/James preferred as the better defender. Assuming the back three is dropped, his utility becomes even worse so he is one of the easier players to remove when trying to create a tournament squad. On the other side we have Chilwell, Trippier, Saka... The latter two in particular have the adaptability and can play either side. So, if I was picking five full backs for England just in case, I'd be going with: Alexander-Arnold, Wan-Bissaka, Chilwell, Saka, and Trippier at this moment in time. Reece James will definitely stake a claim while there are some other good fullbacks who will be in the argument I'm sure, notably Maitland-Niles & Shaw.
I don't have much to say on the CBs as Maguire, Gomez, Mings, and Keane seem like the only four in the argument. I don't see a stand-out fifth so I'd be tempted to just use Rice as cover if there were multiple injuries to save a space in the squad.
I know Henderson will never be left out, but I think England should persist with trying to bank on Rice, Phillips and Winks as the deeper midfield choices after the Euros. Henderson will play as he's the most experienced and plays in a great Liverpool side, I just don't see him bringing enough for much longer. He's lucky England doesn't have a massive selection of quality central midfield players and it is what will hold the national team back the most. It feels a bit like United at the moment, almost needing to play two players who probably aren't the quality you're looking for but provide a much better balance to the side when they play. I'm hopeful that the three players I mentioned develop well enough to be those guys when needed, but I am almost hoping that England can find a way to use just one of them most of the time and mould the likes of Grealish, Mount, and Foden into a system much like how Man City played with De Bruyne & Silva ahead of Fernandinho. I'm hopeful that Rice can be that DM with two of those guys ahead of him in a 433/4123. Of course, if England play one of the big teams then you replace an offensive midfield player for a more defensively solid one. In the near future, my six in the squad is most likely to be: Rice, Phillips, Winks, Grealish, Mount, and Foden. However, you have to give a chance to the likes of Maddison & Ward-Prowse as well, but I think they're more likely to make the squad over a forward if one of them is not performing, rather than replacing one of the six I mentioned already.
Forwards is very interesting but difficult as there's only 23 places in an International Squad for some reason (I personally think it should be 25 even if you can only name 11 subs). If I am to go with what I have said so far, I would be picking 9 Defenders and 6 Midfielders, along with the 3 goalkeepers making 18. That leaves room for only 5 Forwards. Kane, Rashford, Sterling & Sancho are pretty much a given to me. That means I'd have to pick one from Calvert-Lewin, Greenwood, Ings, Hudson-Odoi and quite a few others who I'm forgetting and that's with already leaving out certain players. It's such a hard choice between Calvert-Lewin & Greenwood mainly, but I'd probably give the nod to Dominic right now. It would feel odd not taking Greenwood, but he'll probably have to surpass last season's form if he is to go.
This is what I think Southgate is likely to pick though:
GK: N.Pope, D.Henderson, J.Pickford
DF: T.Alexander-Arnold, K.Walker, B.Chilwell, K.Trippier, B.Saka; H.Maguire, J.Gomez, T.Mings, M.Keane
MF: J.Henderson, D.Rice, E.Dier, P.Foden, M.Mount
FW: H.Kane, M.Rashford, R.Sterling, J.Sancho, J.Grealish, D.Calvert-Lewin
so I figured erm might as well put Grealish there.