Depening on which Brighton fan you ask about which manager, its either that "the players made the manager good" or "the manager made the players good", depending on what the current narrative is.If that were true you’d never get surprise results and who decides if players are better or worse, managers can have a big influence on players, as we Brighton fans know….
As I said, "usually win / usually lose". Yes, sometimes there are surprise results and these can be the result of many things: luck, the players causing the surprise having a good day at the job, the players losing have a bad day, fine margins, freak goals. Once in a while, yes a tactical or strategical move made by the manager will win you the game. But most often it will be down to the quality of the players: if England go and play against... Slovenia, they will win maybe 8 or 9 out of 10 because the footballers are better. If they go and play against France or Argentina, they'll lose maybe 7 out of 10, because their footballers are worse.
Managers in club teams can have more influence on players than manager in club teams. If all the clubs in England are unable to produce three top class midfielders despite having academies and whatnot working on that on a daily basis, then how is Southgate supposed to produce a top class midfield trio when he is only in charge of some 30 training sessions a year?