Yes, you're right; tactics matter a lot. Southgate will hopefully have them set up to defend well. But I think the lack of pace in the England defense is going to make them play a bit deeper, a bit slower and a bit more methodically.
On the right flank of their defense, I think that if they had Reece James, they would have a fair chance of neutralizing Mbappe's raids down the wing. I think Ben Chilwell also would have been better equipped than Shaw at the left back spot. Without those 2 Chelsea wingbacks / fullbacks, I think England suffers a bit defensively.
France misses Pogba and Kante in their midfield, but Rabiot has been really good. I think France is going to have more control of the ball, but if England have a possession advantage, I think it's going to be a bit sterile and in their own end. I don't think that they have that guy in midfield who opens locks - maybe Mason Mount, maybe Grealish (but I see him more as a guy who buys fouls, rather than making the great assist). Foden is a winger. Who is going to direct the attack from England's midfield and open up an agile French defense?