Like when he played 4-4-2 into 4-5-1 into 4-4-1-1 into 4-3-3 into 4-2-3-1, I don’t think 3-4-1-2 would be out of reach for him. Rather we don’t have the player material for it atm and it would take some time is my guess.
If you had the stamford fortress with a squad built for years by defensive-minded Mou, and an absolute expert on coaching it, you buy a defensive piece then yes maybe Conte can do it quickly and successfully with Chelsea. But for us? we have player material for the exact opposite, possession-based attacking football.
Ofc it could be done, but if Wenger did it in 2 weeks that would be absolutely remarkable (incl. our defenders), but maybe it would be more realistic if we bought some version of Bonucci + shifted out two other players next window and spent all summer practising it or something. Also what Leper said, changing formation doesn’t just solve everything anyway.