I don’t think many managers adapt. Even with injured players they still try and play there way. Guardiola does it, the difference is though with injury’s your style of play won’t look as good. Look at how city was without Rodri, they didn’t play as good and I think they lose a couple.
It kind of depends. In Guardiola's case, he won the league at a canter with KDB sidelined and he gets by just fine without Haaland. This team loses without Rodri though, true.
Even Ten Hag adapted last season, going to a double pivot and letting his keeper play hot potato. Managers do adapt all the time - what we 'need' is one who can adapt to never having a left back, a new defence every week, a number of midfielders in sharp decline, and a forward line that is both light on depth and streaky at best.
Shouldn't be too hard to find.