Southgate could easily utilise the simple 4-4-2 but with some modern tactical caveats.
.................... Pickford
Walker - Stones - Guehi - Trippier
Palmer - Bellingham - Rice - Gordon
............... Watkins - Kane
Stones can step up into DM as he does for City, and Walker also doing that Inside WB role he plays for City too where he moves into the right side of CM to help out when we have the ball. TAA does this exact role for Liverpool too.
Bellingham can push forwards and play with the aforementioned Walker/Stones filling the gaps he leaves behind.
Then Kane drops off deep as he likes to do for his clubs and Watkins gives that threat in behind. That combo should stretch the defence around more.
IMO this gets the best out of the squad and gives us more in attack. They can all play this sort of system as they do it week in week out for their clubs, or have done at some point. Bellingham has to play slightly deeper, but he's done that role plenty before.
The big issue is at LB but we knew that coming in to the tournament because Gaz decided only to pick one fit LB the melt.