Rather than answering a specific question, an adaptable essay is formed more generally and conceptually. Focus on the key syllabus points and create an essay around it. Also pre-prepping evidence for quotes/analysis. More so for english, I would create an essay that specifically just analyses texts with a thesis that directly addresses the syllabus. From then, it all comes down to practice and skill for you to create an essay in the exam which answers the question, but also providing an a judgment on the syllabus.
Just note though, because you cant exactly predict the question, there are pros and cons about having an adaptable essay, it just comes down to preference and how well you perform in an exam. some people may struggle creating theses in exam conditions, and others may find it easy to formulate a thesis in an exam. Imo, the safest would be to fully understand texts/content before going into an exam so you fully know all the key points. Personally i dont do humanities like history, but I have heard that people memorise a bunch of essay structures before going into an exam and do quite well.